summaryrefslogtreecommitdiffstats
path: root/libpixelflinger/trap.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'libpixelflinger/trap.cpp')
-rw-r--r--libpixelflinger/trap.cpp1173
1 files changed, 1173 insertions, 0 deletions
diff --git a/libpixelflinger/trap.cpp b/libpixelflinger/trap.cpp
new file mode 100644
index 000000000..30b633f1b
--- /dev/null
+++ b/libpixelflinger/trap.cpp
@@ -0,0 +1,1173 @@
+/* libs/pixelflinger/trap.cpp
+**
+** Copyright 2006, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+** http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "trap.h"
+#include "picker.h"
+
+#include <cutils/log.h>
+#include <cutils/memory.h>
+
+namespace android {
+
+// ----------------------------------------------------------------------------
+
+// enable to see triangles edges
+#define DEBUG_TRANGLES 0
+
+// ----------------------------------------------------------------------------
+
+static void pointx_validate(void *con, const GGLcoord* c, GGLcoord r);
+static void pointx(void *con, const GGLcoord* c, GGLcoord r);
+static void aa_pointx(void *con, const GGLcoord* c, GGLcoord r);
+static void aa_nice_pointx(void *con, const GGLcoord* c, GGLcoord r);
+
+static void linex_validate(void *con, const GGLcoord* v0, const GGLcoord* v1, GGLcoord w);
+static void linex(void *con, const GGLcoord* v0, const GGLcoord* v1, GGLcoord w);
+static void aa_linex(void *con, const GGLcoord* v0, const GGLcoord* v1, GGLcoord w);
+
+static void recti_validate(void* c, GGLint l, GGLint t, GGLint r, GGLint b);
+static void recti(void* c, GGLint l, GGLint t, GGLint r, GGLint b);
+
+static void trianglex_validate(void*,
+ const GGLcoord*, const GGLcoord*, const GGLcoord*);
+static void trianglex_small(void*,
+ const GGLcoord*, const GGLcoord*, const GGLcoord*);
+static void trianglex_big(void*,
+ const GGLcoord*, const GGLcoord*, const GGLcoord*);
+static void aa_trianglex(void*,
+ const GGLcoord*, const GGLcoord*, const GGLcoord*);
+static void trianglex_debug(void* con,
+ const GGLcoord*, const GGLcoord*, const GGLcoord*);
+
+static void aapolyx(void* con,
+ const GGLcoord* pts, int count);
+
+static inline int min(int a, int b) CONST;
+static inline int max(int a, int b) CONST;
+static inline int min(int a, int b, int c) CONST;
+static inline int max(int a, int b, int c) CONST;
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#pragma mark Tools
+#endif
+
+inline int min(int a, int b) {
+ return a<b ? a : b;
+}
+inline int max(int a, int b) {
+ return a<b ? b : a;
+}
+inline int min(int a, int b, int c) {
+ return min(a,min(b,c));
+}
+inline int max(int a, int b, int c) {
+ return max(a,max(b,c));
+}
+
+template <typename T>
+static inline void swap(T& a, T& b) {
+ T t(a);
+ a = b;
+ b = t;
+}
+
+static void
+triangle_dump_points( const GGLcoord* v0,
+ const GGLcoord* v1,
+ const GGLcoord* v2 )
+{
+ float tri = 1.0f / TRI_ONE;
+ LOGD( " P0=(%.3f, %.3f) [%08x, %08x]\n"
+ " P1=(%.3f, %.3f) [%08x, %08x]\n"
+ " P2=(%.3f, %.3f) [%08x, %08x]\n",
+ v0[0]*tri, v0[1]*tri, v0[0], v0[1],
+ v1[0]*tri, v1[1]*tri, v1[0], v1[1],
+ v2[0]*tri, v2[1]*tri, v2[0], v2[1] );
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#pragma mark Misc
+#endif
+
+void ggl_init_trap(context_t* c)
+{
+ ggl_state_changed(c, GGL_PIXEL_PIPELINE_STATE|GGL_TMU_STATE|GGL_CB_STATE);
+}
+
+void ggl_state_changed(context_t* c, int flags)
+{
+ if (ggl_likely(!c->dirty)) {
+ c->procs.pointx = pointx_validate;
+ c->procs.linex = linex_validate;
+ c->procs.recti = recti_validate;
+ c->procs.trianglex = trianglex_validate;
+ }
+ c->dirty |= uint32_t(flags);
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#pragma mark Point
+#endif
+
+void pointx_validate(void *con, const GGLcoord* v, GGLcoord rad)
+{
+ GGL_CONTEXT(c, con);
+ ggl_pick(c);
+ if (c->state.needs.p & GGL_NEED_MASK(P_AA)) {
+ if (c->state.enables & GGL_ENABLE_POINT_AA_NICE) {
+ c->procs.pointx = aa_nice_pointx;
+ } else {
+ c->procs.pointx = aa_pointx;
+ }
+ } else {
+ c->procs.pointx = pointx;
+ }
+ c->procs.pointx(con, v, rad);
+}
+
+void pointx(void *con, const GGLcoord* v, GGLcoord rad)
+{
+ GGL_CONTEXT(c, con);
+ GGLcoord halfSize = TRI_ROUND(rad) >> 1;
+ if (halfSize == 0)
+ halfSize = TRI_HALF;
+ GGLcoord xc = v[0];
+ GGLcoord yc = v[1];
+ if (halfSize & TRI_HALF) { // size odd
+ xc = TRI_FLOOR(xc) + TRI_HALF;
+ yc = TRI_FLOOR(yc) + TRI_HALF;
+ } else { // size even
+ xc = TRI_ROUND(xc);
+ yc = TRI_ROUND(yc);
+ }
+ GGLint l = (xc - halfSize) >> TRI_FRACTION_BITS;
+ GGLint t = (yc - halfSize) >> TRI_FRACTION_BITS;
+ GGLint r = (xc + halfSize) >> TRI_FRACTION_BITS;
+ GGLint b = (yc + halfSize) >> TRI_FRACTION_BITS;
+ recti(c, l, t, r, b);
+}
+
+// This way of computing the coverage factor, is more accurate and gives
+// better results for small circles, but it is also a lot slower.
+// Here we use super-sampling.
+static int32_t coverageNice(GGLcoord x, GGLcoord y,
+ GGLcoord rmin, GGLcoord rmax, GGLcoord rr)
+{
+ const GGLcoord d2 = x*x + y*y;
+ if (d2 >= rmax) return 0;
+ if (d2 < rmin) return 0x7FFF;
+
+ const int kSamples = 4;
+ const int kInc = 4; // 1/4 = 0.25
+ const int kCoverageUnit = 1; // 1/(4^2) = 0.0625
+ const GGLcoord kCoordOffset = -6; // -0.375
+
+ int hits = 0;
+ int x_sample = x + kCoordOffset;
+ for (int i=0 ; i<kSamples ; i++, x_sample += kInc) {
+ const int xval = rr - (x_sample * x_sample);
+ int y_sample = y + kCoordOffset;
+ for (int j=0 ; j<kSamples ; j++, y_sample += kInc) {
+ if (xval - (y_sample * y_sample) > 0)
+ hits += kCoverageUnit;
+ }
+ }
+ return min(0x7FFF, hits << (15 - kSamples));
+}
+
+
+void aa_nice_pointx(void *con, const GGLcoord* v, GGLcoord size)
+{
+ GGL_CONTEXT(c, con);
+
+ GGLcoord rad = ((size + 1)>>1);
+ GGLint l = (v[0] - rad) >> TRI_FRACTION_BITS;
+ GGLint t = (v[1] - rad) >> TRI_FRACTION_BITS;
+ GGLint r = (v[0] + rad + (TRI_ONE-1)) >> TRI_FRACTION_BITS;
+ GGLint b = (v[1] + rad + (TRI_ONE-1)) >> TRI_FRACTION_BITS;
+ GGLcoord xstart = TRI_FROM_INT(l) - v[0] + TRI_HALF;
+ GGLcoord ystart = TRI_FROM_INT(t) - v[1] + TRI_HALF;
+
+ // scissor...
+ if (l < GGLint(c->state.scissor.left)) {
+ xstart += TRI_FROM_INT(c->state.scissor.left-l);
+ l = GGLint(c->state.scissor.left);
+ }
+ if (t < GGLint(c->state.scissor.top)) {
+ ystart += TRI_FROM_INT(c->state.scissor.top-t);
+ t = GGLint(c->state.scissor.top);
+ }
+ if (r > GGLint(c->state.scissor.right)) {
+ r = GGLint(c->state.scissor.right);
+ }
+ if (b > GGLint(c->state.scissor.bottom)) {
+ b = GGLint(c->state.scissor.bottom);
+ }
+
+ int xc = r - l;
+ int yc = b - t;
+ if (xc>0 && yc>0) {
+ int16_t* covPtr = c->state.buffers.coverage;
+ const int32_t sqr2Over2 = 0xC; // rounded up
+ GGLcoord rr = rad*rad;
+ GGLcoord rmin = (rad - sqr2Over2)*(rad - sqr2Over2);
+ GGLcoord rmax = (rad + sqr2Over2)*(rad + sqr2Over2);
+ GGLcoord y = ystart;
+ c->iterators.xl = l;
+ c->iterators.xr = r;
+ c->init_y(c, t);
+ do {
+ // compute coverage factors for each pixel
+ GGLcoord x = xstart;
+ for (int i=l ; i<r ; i++) {
+ covPtr[i] = coverageNice(x, y, rmin, rmax, rr);
+ x += TRI_ONE;
+ }
+ y += TRI_ONE;
+ c->scanline(c);
+ c->step_y(c);
+ } while (--yc);
+ }
+}
+
+// This is a cheap way of computing the coverage factor for a circle.
+// We just lerp between the circles of radii r-sqrt(2)/2 and r+sqrt(2)/2
+static inline int32_t coverageFast(GGLcoord x, GGLcoord y,
+ GGLcoord rmin, GGLcoord rmax, GGLcoord scale)
+{
+ const GGLcoord d2 = x*x + y*y;
+ if (d2 >= rmax) return 0;
+ if (d2 < rmin) return 0x7FFF;
+ return 0x7FFF - (d2-rmin)*scale;
+}
+
+void aa_pointx(void *con, const GGLcoord* v, GGLcoord size)
+{
+ GGL_CONTEXT(c, con);
+
+ GGLcoord rad = ((size + 1)>>1);
+ GGLint l = (v[0] - rad) >> TRI_FRACTION_BITS;
+ GGLint t = (v[1] - rad) >> TRI_FRACTION_BITS;
+ GGLint r = (v[0] + rad + (TRI_ONE-1)) >> TRI_FRACTION_BITS;
+ GGLint b = (v[1] + rad + (TRI_ONE-1)) >> TRI_FRACTION_BITS;
+ GGLcoord xstart = TRI_FROM_INT(l) - v[0] + TRI_HALF;
+ GGLcoord ystart = TRI_FROM_INT(t) - v[1] + TRI_HALF;
+
+ // scissor...
+ if (l < GGLint(c->state.scissor.left)) {
+ xstart += TRI_FROM_INT(c->state.scissor.left-l);
+ l = GGLint(c->state.scissor.left);
+ }
+ if (t < GGLint(c->state.scissor.top)) {
+ ystart += TRI_FROM_INT(c->state.scissor.top-t);
+ t = GGLint(c->state.scissor.top);
+ }
+ if (r > GGLint(c->state.scissor.right)) {
+ r = GGLint(c->state.scissor.right);
+ }
+ if (b > GGLint(c->state.scissor.bottom)) {
+ b = GGLint(c->state.scissor.bottom);
+ }
+
+ int xc = r - l;
+ int yc = b - t;
+ if (xc>0 && yc>0) {
+ int16_t* covPtr = c->state.buffers.coverage;
+ rad <<= 4;
+ const int32_t sqr2Over2 = 0xB5; // fixed-point 24.8
+ GGLcoord rmin = rad - sqr2Over2;
+ GGLcoord rmax = rad + sqr2Over2;
+ GGLcoord scale;
+ rmin *= rmin;
+ rmax *= rmax;
+ scale = 0x800000 / (rmax - rmin);
+ rmin >>= 8;
+ rmax >>= 8;
+
+ GGLcoord y = ystart;
+ c->iterators.xl = l;
+ c->iterators.xr = r;
+ c->init_y(c, t);
+
+ do {
+ // compute coverage factors for each pixel
+ GGLcoord x = xstart;
+ for (int i=l ; i<r ; i++) {
+ covPtr[i] = coverageFast(x, y, rmin, rmax, scale);
+ x += TRI_ONE;
+ }
+ y += TRI_ONE;
+ c->scanline(c);
+ c->step_y(c);
+ } while (--yc);
+ }
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#pragma mark Line
+#endif
+
+void linex_validate(void *con, const GGLcoord* v0, const GGLcoord* v1, GGLcoord w)
+{
+ GGL_CONTEXT(c, con);
+ ggl_pick(c);
+ if (c->state.needs.p & GGL_NEED_MASK(P_AA)) {
+ c->procs.linex = aa_linex;
+ } else {
+ c->procs.linex = linex;
+ }
+ c->procs.linex(con, v0, v1, w);
+}
+
+static void linex(void *con, const GGLcoord* v0, const GGLcoord* v1, GGLcoord width)
+{
+ GGL_CONTEXT(c, con);
+ GGLcoord v[4][2];
+ v[0][0] = v0[0]; v[0][1] = v0[1];
+ v[1][0] = v1[0]; v[1][1] = v1[1];
+ v0 = v[0];
+ v1 = v[1];
+ const GGLcoord dx = abs(v0[0] - v1[0]);
+ const GGLcoord dy = abs(v0[1] - v1[1]);
+ GGLcoord nx, ny;
+ nx = ny = 0;
+
+ GGLcoord halfWidth = TRI_ROUND(width) >> 1;
+ if (halfWidth == 0)
+ halfWidth = TRI_HALF;
+
+ ((dx > dy) ? ny : nx) = halfWidth;
+ v[2][0] = v1[0]; v[2][1] = v1[1];
+ v[3][0] = v0[0]; v[3][1] = v0[1];
+ v[0][0] += nx; v[0][1] += ny;
+ v[1][0] += nx; v[1][1] += ny;
+ v[2][0] -= nx; v[2][1] -= ny;
+ v[3][0] -= nx; v[3][1] -= ny;
+ trianglex_big(con, v[0], v[1], v[2]);
+ trianglex_big(con, v[0], v[2], v[3]);
+}
+
+static void aa_linex(void *con, const GGLcoord* v0, const GGLcoord* v1, GGLcoord width)
+{
+ GGL_CONTEXT(c, con);
+ GGLcoord v[4][2];
+ v[0][0] = v0[0]; v[0][1] = v0[1];
+ v[1][0] = v1[0]; v[1][1] = v1[1];
+ v0 = v[0];
+ v1 = v[1];
+
+ const GGLcoord dx = v0[0] - v1[0];
+ const GGLcoord dy = v0[1] - v1[1];
+ GGLcoord nx = -dy;
+ GGLcoord ny = dx;
+
+ // generally, this will be well below 1.0
+ const GGLfixed norm = gglMulx(width, gglSqrtRecipx(nx*nx+ny*ny), 4);
+ nx = gglMulx(nx, norm, 21);
+ ny = gglMulx(ny, norm, 21);
+
+ v[2][0] = v1[0]; v[2][1] = v1[1];
+ v[3][0] = v0[0]; v[3][1] = v0[1];
+ v[0][0] += nx; v[0][1] += ny;
+ v[1][0] += nx; v[1][1] += ny;
+ v[2][0] -= nx; v[2][1] -= ny;
+ v[3][0] -= nx; v[3][1] -= ny;
+ aapolyx(con, v[0], 4);
+}
+
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#pragma mark Rect
+#endif
+
+void recti_validate(void *con, GGLint l, GGLint t, GGLint r, GGLint b)
+{
+ GGL_CONTEXT(c, con);
+ ggl_pick(c);
+ c->procs.recti = recti;
+ c->procs.recti(con, l, t, r, b);
+}
+
+void recti(void* con, GGLint l, GGLint t, GGLint r, GGLint b)
+{
+ GGL_CONTEXT(c, con);
+
+ // scissor...
+ if (l < GGLint(c->state.scissor.left))
+ l = GGLint(c->state.scissor.left);
+ if (t < GGLint(c->state.scissor.top))
+ t = GGLint(c->state.scissor.top);
+ if (r > GGLint(c->state.scissor.right))
+ r = GGLint(c->state.scissor.right);
+ if (b > GGLint(c->state.scissor.bottom))
+ b = GGLint(c->state.scissor.bottom);
+
+ int xc = r - l;
+ int yc = b - t;
+ if (xc>0 && yc>0) {
+ c->iterators.xl = l;
+ c->iterators.xr = r;
+ c->init_y(c, t);
+ c->rect(c, yc);
+ }
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#pragma mark Triangle / Debugging
+#endif
+
+static void scanline_set(context_t* c)
+{
+ int32_t x = c->iterators.xl;
+ size_t ct = c->iterators.xr - x;
+ int32_t y = c->iterators.y;
+ surface_t* cb = &(c->state.buffers.color);
+ const GGLFormat* fp = &(c->formats[cb->format]);
+ uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
+ (x + (cb->stride * y)) * fp->size;
+ const size_t size = ct * fp->size;
+ memset(dst, 0xFF, size);
+}
+
+static void trianglex_debug(void* con,
+ const GGLcoord* v0, const GGLcoord* v1, const GGLcoord* v2)
+{
+ GGL_CONTEXT(c, con);
+ if (c->state.needs.p & GGL_NEED_MASK(P_AA)) {
+ aa_trianglex(con,v0,v1,v2);
+ } else {
+ trianglex_big(con,v0,v1,v2);
+ }
+ void (*save_scanline)(context_t*) = c->scanline;
+ c->scanline = scanline_set;
+ linex(con, v0, v1, TRI_ONE);
+ linex(con, v1, v2, TRI_ONE);
+ linex(con, v2, v0, TRI_ONE);
+ c->scanline = save_scanline;
+}
+
+static void trianglex_xor(void* con,
+ const GGLcoord* v0, const GGLcoord* v1, const GGLcoord* v2)
+{
+ trianglex_big(con,v0,v1,v2);
+ trianglex_small(con,v0,v1,v2);
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#pragma mark Triangle
+#endif
+
+void trianglex_validate(void *con,
+ const GGLcoord* v0, const GGLcoord* v1, const GGLcoord* v2)
+{
+ GGL_CONTEXT(c, con);
+ ggl_pick(c);
+ if (c->state.needs.p & GGL_NEED_MASK(P_AA)) {
+ c->procs.trianglex = DEBUG_TRANGLES ? trianglex_debug : aa_trianglex;
+ } else {
+ c->procs.trianglex = DEBUG_TRANGLES ? trianglex_debug : trianglex_big;
+ }
+ c->procs.trianglex(con, v0, v1, v2);
+}
+
+// ----------------------------------------------------------------------------
+
+void trianglex_small(void* con,
+ const GGLcoord* v0, const GGLcoord* v1, const GGLcoord* v2)
+{
+ GGL_CONTEXT(c, con);
+
+ // vertices are in 28.4 fixed point, which allows
+ // us to use 32 bits multiplies below.
+ int32_t x0 = v0[0];
+ int32_t y0 = v0[1];
+ int32_t x1 = v1[0];
+ int32_t y1 = v1[1];
+ int32_t x2 = v2[0];
+ int32_t y2 = v2[1];
+
+ int32_t dx01 = x0 - x1;
+ int32_t dy20 = y2 - y0;
+ int32_t dy01 = y0 - y1;
+ int32_t dx20 = x2 - x0;
+
+ // The code below works only with CCW triangles
+ // so if we get a CW triangle, we need to swap two of its vertices
+ if (dx01*dy20 < dy01*dx20) {
+ swap(x0, x1);
+ swap(y0, y1);
+ dx01 = x0 - x1;
+ dy01 = y0 - y1;
+ dx20 = x2 - x0;
+ dy20 = y2 - y0;
+ }
+ int32_t dx12 = x1 - x2;
+ int32_t dy12 = y1 - y2;
+
+ // bounding box & scissor
+ const int32_t bminx = TRI_FLOOR(min(x0, x1, x2)) >> TRI_FRACTION_BITS;
+ const int32_t bminy = TRI_FLOOR(min(y0, y1, y2)) >> TRI_FRACTION_BITS;
+ const int32_t bmaxx = TRI_CEIL( max(x0, x1, x2)) >> TRI_FRACTION_BITS;
+ const int32_t bmaxy = TRI_CEIL( max(y0, y1, y2)) >> TRI_FRACTION_BITS;
+ const int32_t minx = max(bminx, c->state.scissor.left);
+ const int32_t miny = max(bminy, c->state.scissor.top);
+ const int32_t maxx = min(bmaxx, c->state.scissor.right);
+ const int32_t maxy = min(bmaxy, c->state.scissor.bottom);
+ if ((minx >= maxx) || (miny >= maxy))
+ return; // too small or clipped out...
+
+ // step equations to the bounding box and snap to pixel center
+ const int32_t my = (miny << TRI_FRACTION_BITS) + TRI_HALF;
+ const int32_t mx = (minx << TRI_FRACTION_BITS) + TRI_HALF;
+ int32_t ey0 = dy01 * (x0 - mx) - dx01 * (y0 - my);
+ int32_t ey1 = dy12 * (x1 - mx) - dx12 * (y1 - my);
+ int32_t ey2 = dy20 * (x2 - mx) - dx20 * (y2 - my);
+
+ // right-exclusive fill rule, to avoid rare cases
+ // of over drawing
+ if (dy01<0 || (dy01 == 0 && dx01>0)) ey0++;
+ if (dy12<0 || (dy12 == 0 && dx12>0)) ey1++;
+ if (dy20<0 || (dy20 == 0 && dx20>0)) ey2++;
+
+ c->init_y(c, miny);
+ for (int32_t y = miny; y < maxy; y++) {
+ register int32_t ex0 = ey0;
+ register int32_t ex1 = ey1;
+ register int32_t ex2 = ey2;
+ register int32_t xl, xr;
+ for (xl=minx ; xl<maxx ; xl++) {
+ if (ex0>0 && ex1>0 && ex2>0)
+ break; // all strictly positive
+ ex0 -= dy01 << TRI_FRACTION_BITS;
+ ex1 -= dy12 << TRI_FRACTION_BITS;
+ ex2 -= dy20 << TRI_FRACTION_BITS;
+ }
+ xr = xl;
+ for ( ; xr<maxx ; xr++) {
+ if (!(ex0>0 && ex1>0 && ex2>0))
+ break; // not all strictly positive
+ ex0 -= dy01 << TRI_FRACTION_BITS;
+ ex1 -= dy12 << TRI_FRACTION_BITS;
+ ex2 -= dy20 << TRI_FRACTION_BITS;
+ }
+
+ if (xl < xr) {
+ c->iterators.xl = xl;
+ c->iterators.xr = xr;
+ c->scanline(c);
+ }
+ c->step_y(c);
+
+ ey0 += dx01 << TRI_FRACTION_BITS;
+ ey1 += dx12 << TRI_FRACTION_BITS;
+ ey2 += dx20 << TRI_FRACTION_BITS;
+ }
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#endif
+
+// the following routine fills a triangle via edge stepping, which
+// unfortunately requires divisions in the setup phase to get right,
+// it should probably only be used for relatively large trianges
+
+
+// x = y*DX/DY (ou DX and DY are constants, DY > 0, et y >= 0)
+//
+// for an equation of the type:
+// x' = y*K/2^p (with K and p constants "carefully chosen")
+//
+// We can now do a DDA without precision loss. We define 'e' by:
+// x' - x = y*(DX/DY - K/2^p) = y*e
+//
+// If we choose K = round(DX*2^p/DY) then,
+// abs(e) <= 1/2^(p+1) by construction
+//
+// therefore abs(x'-x) = y*abs(e) <= y/2^(p+1) <= DY/2^(p+1) <= DMAX/2^(p+1)
+//
+// which means that if DMAX <= 2^p, therefore abs(x-x') <= 1/2, including
+// at the last line. In fact, it's even a strict inequality except in one
+// extrem case (DY == DMAX et e = +/- 1/2)
+//
+// Applying that to our coordinates, we need 2^p >= 4096*16 = 65536
+// so p = 16 is enough, we're so lucky!
+
+const int TRI_ITERATORS_BITS = 16;
+
+struct Edge
+{
+ int32_t x; // edge position in 16.16 coordinates
+ int32_t x_incr; // on each step, increment x by that amount
+ int32_t y_top; // starting scanline, 16.4 format
+ int32_t y_bot;
+};
+
+static void
+edge_dump( Edge* edge )
+{
+ LOGI( " top=%d (%.3f) bot=%d (%.3f) x=%d (%.3f) ix=%d (%.3f)",
+ edge->y_top, edge->y_top/float(TRI_ONE),
+ edge->y_bot, edge->y_bot/float(TRI_ONE),
+ edge->x, edge->x/float(FIXED_ONE),
+ edge->x_incr, edge->x_incr/float(FIXED_ONE) );
+}
+
+static void
+triangle_dump_edges( Edge* edges,
+ int count )
+{
+ LOGI( "%d edge%s:\n", count, count == 1 ? "" : "s" );
+ for ( ; count > 0; count--, edges++ )
+ edge_dump( edges );
+}
+
+// the following function sets up an edge, it assumes
+// that ymin and ymax are in already in the 'reduced'
+// format
+static __attribute__((noinline))
+void edge_setup(
+ Edge* edges,
+ int* pcount,
+ const GGLcoord* p1,
+ const GGLcoord* p2,
+ int32_t ymin,
+ int32_t ymax )
+{
+ const GGLfixed* top = p1;
+ const GGLfixed* bot = p2;
+ Edge* edge = edges + *pcount;
+
+ if (top[1] > bot[1]) {
+ swap(top, bot);
+ }
+
+ int y1 = top[1] | 1;
+ int y2 = bot[1] | 1;
+ int dy = y2 - y1;
+
+ if ( dy == 0 || y1 > ymax || y2 < ymin )
+ return;
+
+ if ( y1 > ymin )
+ ymin = TRI_SNAP_NEXT_HALF(y1);
+
+ if ( y2 < ymax )
+ ymax = TRI_SNAP_PREV_HALF(y2);
+
+ if ( ymin > ymax ) // when the edge doesn't cross any scanline
+ return;
+
+ const int x1 = top[0];
+ const int dx = bot[0] - x1;
+ const int shift = TRI_ITERATORS_BITS - TRI_FRACTION_BITS;
+
+ // setup edge fields
+ // We add 0.5 to edge->x here because it simplifies the rounding
+ // in triangle_sweep_edges() -- this doesn't change the ordering of 'x'
+ edge->x = (x1 << shift) + (1LU << (TRI_ITERATORS_BITS-1));
+ edge->x_incr = 0;
+ edge->y_top = ymin;
+ edge->y_bot = ymax;
+
+ if (ggl_likely(ymin <= ymax && dx)) {
+ edge->x_incr = gglDivQ16(dx, dy);
+ }
+ if (ggl_likely(y1 < ymin)) {
+ int32_t xadjust = (edge->x_incr * (ymin-y1)) >> TRI_FRACTION_BITS;
+ edge->x += xadjust;
+ }
+
+ ++*pcount;
+}
+
+
+static void
+triangle_sweep_edges( Edge* left,
+ Edge* right,
+ int ytop,
+ int ybot,
+ context_t* c )
+{
+ int count = ((ybot - ytop)>>TRI_FRACTION_BITS) + 1;
+ if (count<=0) return;
+
+ // sort the edges horizontally
+ if ((left->x > right->x) ||
+ ((left->x == right->x) && (left->x_incr > right->x_incr))) {
+ swap(left, right);
+ }
+
+ int left_x = left->x;
+ int right_x = right->x;
+ const int left_xi = left->x_incr;
+ const int right_xi = right->x_incr;
+ left->x += left_xi * count;
+ right->x += right_xi * count;
+
+ const int xmin = c->state.scissor.left;
+ const int xmax = c->state.scissor.right;
+ do {
+ // horizontal scissoring
+ const int32_t xl = max(left_x >> TRI_ITERATORS_BITS, xmin);
+ const int32_t xr = min(right_x >> TRI_ITERATORS_BITS, xmax);
+ left_x += left_xi;
+ right_x += right_xi;
+ // invoke the scanline rasterizer
+ if (ggl_likely(xl < xr)) {
+ c->iterators.xl = xl;
+ c->iterators.xr = xr;
+ c->scanline(c);
+ }
+ c->step_y(c);
+ } while (--count);
+}
+
+
+void trianglex_big(void* con,
+ const GGLcoord* v0, const GGLcoord* v1, const GGLcoord* v2)
+{
+ GGL_CONTEXT(c, con);
+
+ Edge edges[3];
+ int num_edges = 0;
+ int32_t ymin = TRI_FROM_INT(c->state.scissor.top) + TRI_HALF;
+ int32_t ymax = TRI_FROM_INT(c->state.scissor.bottom) - TRI_HALF;
+
+ edge_setup( edges, &num_edges, v0, v1, ymin, ymax );
+ edge_setup( edges, &num_edges, v0, v2, ymin, ymax );
+ edge_setup( edges, &num_edges, v1, v2, ymin, ymax );
+
+ if (ggl_unlikely(num_edges<2)) // for really tiny triangles that don't
+ return; // cross any scanline centers
+
+ Edge* left = &edges[0];
+ Edge* right = &edges[1];
+ Edge* other = &edges[2];
+ int32_t y_top = min(left->y_top, right->y_top);
+ int32_t y_bot = max(left->y_bot, right->y_bot);
+
+ if (ggl_likely(num_edges==3)) {
+ y_top = min(y_top, edges[2].y_top);
+ y_bot = max(y_bot, edges[2].y_bot);
+ if (edges[0].y_top > y_top) {
+ other = &edges[0];
+ left = &edges[2];
+ } else if (edges[1].y_top > y_top) {
+ other = &edges[1];
+ right = &edges[2];
+ }
+ }
+
+ c->init_y(c, y_top >> TRI_FRACTION_BITS);
+
+ int32_t y_mid = min(left->y_bot, right->y_bot);
+ triangle_sweep_edges( left, right, y_top, y_mid, c );
+
+ // second scanline sweep loop, if necessary
+ y_mid += TRI_ONE;
+ if (y_mid <= y_bot) {
+ ((left->y_bot == y_bot) ? right : left) = other;
+ if (other->y_top < y_mid) {
+ other->x += other->x_incr;
+ }
+ triangle_sweep_edges( left, right, y_mid, y_bot, c );
+ }
+}
+
+void aa_trianglex(void* con,
+ const GGLcoord* a, const GGLcoord* b, const GGLcoord* c)
+{
+ GGLcoord pts[6] = { a[0], a[1], b[0], b[1], c[0], c[1] };
+ aapolyx(con, pts, 3);
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#endif
+
+struct AAEdge
+{
+ GGLfixed x; // edge position in 12.16 coordinates
+ GGLfixed x_incr; // on each y step, increment x by that amount
+ GGLfixed y_incr; // on each x step, increment y by that amount
+ int16_t y_top; // starting scanline, 12.4 format
+ int16_t y_bot; // starting scanline, 12.4 format
+ void dump();
+};
+
+void AAEdge::dump()
+{
+ float tri = 1.0f / TRI_ONE;
+ float iter = 1.0f / (1<<TRI_ITERATORS_BITS);
+ float fix = 1.0f / FIXED_ONE;
+ LOGD( "x=%08x (%.3f), "
+ "x_incr=%08x (%.3f), y_incr=%08x (%.3f), "
+ "y_top=%08x (%.3f), y_bot=%08x (%.3f) ",
+ x, x*fix,
+ x_incr, x_incr*iter,
+ y_incr, y_incr*iter,
+ y_top, y_top*tri,
+ y_bot, y_bot*tri );
+}
+
+// the following function sets up an edge, it assumes
+// that ymin and ymax are in already in the 'reduced'
+// format
+static __attribute__((noinline))
+void aa_edge_setup(
+ AAEdge* edges,
+ int* pcount,
+ const GGLcoord* p1,
+ const GGLcoord* p2,
+ int32_t ymin,
+ int32_t ymax )
+{
+ const GGLfixed* top = p1;
+ const GGLfixed* bot = p2;
+ AAEdge* edge = edges + *pcount;
+
+ if (top[1] > bot[1])
+ swap(top, bot);
+
+ int y1 = top[1];
+ int y2 = bot[1];
+ int dy = y2 - y1;
+
+ if (dy==0 || y1>ymax || y2<ymin)
+ return;
+
+ if (y1 > ymin)
+ ymin = y1;
+
+ if (y2 < ymax)
+ ymax = y2;
+
+ const int x1 = top[0];
+ const int dx = bot[0] - x1;
+ const int shift = FIXED_BITS - TRI_FRACTION_BITS;
+
+ // setup edge fields
+ edge->x = x1 << shift;
+ edge->x_incr = 0;
+ edge->y_top = ymin;
+ edge->y_bot = ymax;
+ edge->y_incr = 0x7FFFFFFF;
+
+ if (ggl_likely(ymin <= ymax && dx)) {
+ edge->x_incr = gglDivQ16(dx, dy);
+ if (dx != 0) {
+ edge->y_incr = abs(gglDivQ16(dy, dx));
+ }
+ }
+ if (ggl_likely(y1 < ymin)) {
+ int32_t xadjust = (edge->x_incr * (ymin-y1))
+ >> (TRI_FRACTION_BITS + TRI_ITERATORS_BITS - FIXED_BITS);
+ edge->x += xadjust;
+ }
+
+ ++*pcount;
+}
+
+
+typedef int (*compar_t)(const void*, const void*);
+static int compare_edges(const AAEdge *e0, const AAEdge *e1) {
+ if (e0->y_top > e1->y_top) return 1;
+ if (e0->y_top < e1->y_top) return -1;
+ if (e0->x > e1->x) return 1;
+ if (e0->x < e1->x) return -1;
+ if (e0->x_incr > e1->x_incr) return 1;
+ if (e0->x_incr < e1->x_incr) return -1;
+ return 0; // same edges, should never happen
+}
+
+static inline
+void SET_COVERAGE(int16_t*& p, int32_t value, ssize_t n)
+{
+ android_memset16((uint16_t*)p, value, n*2);
+ p += n;
+}
+
+static inline
+void ADD_COVERAGE(int16_t*& p, int32_t value)
+{
+ value = *p + value;
+ if (value >= 0x8000)
+ value = 0x7FFF;
+ *p++ = value;
+}
+
+static inline
+void SUB_COVERAGE(int16_t*& p, int32_t value)
+{
+ value = *p - value;
+ value &= ~(value>>31);
+ *p++ = value;
+}
+
+void aapolyx(void* con,
+ const GGLcoord* pts, int count)
+{
+ /*
+ * NOTE: This routine assumes that the polygon has been clipped to the
+ * viewport already, that is, no vertex lies outside of the framebuffer.
+ * If this happens, the code below won't corrupt memory but the
+ * coverage values may not be correct.
+ */
+
+ GGL_CONTEXT(c, con);
+
+ // we do only quads for now (it's used for thick lines)
+ if ((count>4) || (count<2)) return;
+
+ // take scissor into account
+ const int xmin = c->state.scissor.left;
+ const int xmax = c->state.scissor.right;
+ if (xmin >= xmax) return;
+
+ // generate edges from the vertices
+ int32_t ymin = TRI_FROM_INT(c->state.scissor.top);
+ int32_t ymax = TRI_FROM_INT(c->state.scissor.bottom);
+ if (ymin >= ymax) return;
+
+ AAEdge edges[4];
+ int num_edges = 0;
+ GGLcoord const * p = pts;
+ for (int i=0 ; i<count-1 ; i++, p+=2) {
+ aa_edge_setup(edges, &num_edges, p, p+2, ymin, ymax);
+ }
+ aa_edge_setup(edges, &num_edges, p, pts, ymin, ymax );
+ if (ggl_unlikely(num_edges<2))
+ return;
+
+ // sort the edge list top to bottom, left to right.
+ qsort(edges, num_edges, sizeof(AAEdge), (compar_t)compare_edges);
+
+ int16_t* const covPtr = c->state.buffers.coverage;
+ memset(covPtr+xmin, 0, (xmax-xmin)*sizeof(*covPtr));
+
+ // now, sweep all edges in order
+ // start with the 2 first edges. We know that they share their top
+ // vertex, by construction.
+ int i = 2;
+ AAEdge* left = &edges[0];
+ AAEdge* right = &edges[1];
+ int32_t yt = left->y_top;
+ GGLfixed l = left->x;
+ GGLfixed r = right->x;
+ int retire = 0;
+ int16_t* coverage;
+
+ // at this point we can initialize the rasterizer
+ c->init_y(c, yt>>TRI_FRACTION_BITS);
+ c->iterators.xl = xmax;
+ c->iterators.xr = xmin;
+
+ do {
+ int32_t y = min(min(left->y_bot, right->y_bot), TRI_FLOOR(yt + TRI_ONE));
+ const int32_t shift = TRI_FRACTION_BITS + TRI_ITERATORS_BITS - FIXED_BITS;
+ const int cf_shift = (1 + TRI_FRACTION_BITS*2 + TRI_ITERATORS_BITS - 15);
+
+ // compute xmin and xmax for the left edge
+ GGLfixed l_min = gglMulAddx(left->x_incr, y - left->y_top, left->x, shift);
+ GGLfixed l_max = l;
+ l = l_min;
+ if (l_min > l_max)
+ swap(l_min, l_max);
+
+ // compute xmin and xmax for the right edge
+ GGLfixed r_min = gglMulAddx(right->x_incr, y - right->y_top, right->x, shift);
+ GGLfixed r_max = r;
+ r = r_min;
+ if (r_min > r_max)
+ swap(r_min, r_max);
+
+ // make sure we're not touching coverage values outside of the
+ // framebuffer
+ l_min &= ~(l_min>>31);
+ r_min &= ~(r_min>>31);
+ l_max &= ~(l_max>>31);
+ r_max &= ~(r_max>>31);
+ if (gglFixedToIntFloor(l_min) >= xmax) l_min = gglIntToFixed(xmax)-1;
+ if (gglFixedToIntFloor(r_min) >= xmax) r_min = gglIntToFixed(xmax)-1;
+ if (gglFixedToIntCeil(l_max) >= xmax) l_max = gglIntToFixed(xmax)-1;
+ if (gglFixedToIntCeil(r_max) >= xmax) r_max = gglIntToFixed(xmax)-1;
+
+ // compute the integer versions of the above
+ const GGLfixed l_min_i = gglFloorx(l_min);
+ const GGLfixed l_max_i = gglCeilx (l_max);
+ const GGLfixed r_min_i = gglFloorx(r_min);
+ const GGLfixed r_max_i = gglCeilx (r_max);
+
+ // clip horizontally using the scissor
+ const int xml = max(xmin, gglFixedToIntFloor(l_min_i));
+ const int xmr = min(xmax, gglFixedToIntFloor(r_max_i));
+
+ // if we just stepped to a new scanline, render the previous one.
+ // and clear the coverage buffer
+ if (retire) {
+ if (c->iterators.xl < c->iterators.xr)
+ c->scanline(c);
+ c->step_y(c);
+ memset(covPtr+xmin, 0, (xmax-xmin)*sizeof(*covPtr));
+ c->iterators.xl = xml;
+ c->iterators.xr = xmr;
+ } else {
+ // update the horizontal range of this scanline
+ c->iterators.xl = min(c->iterators.xl, xml);
+ c->iterators.xr = max(c->iterators.xr, xmr);
+ }
+
+ coverage = covPtr + gglFixedToIntFloor(l_min_i);
+ if (l_min_i == gglFloorx(l_max)) {
+
+ /*
+ * fully traverse this pixel vertically
+ * l_max
+ * +-----/--+ yt
+ * | / |
+ * | / |
+ * | / |
+ * +-/------+ y
+ * l_min (l_min_i + TRI_ONE)
+ */
+
+ GGLfixed dx = l_max - l_min;
+ int32_t dy = y - yt;
+ int cf = gglMulx((dx >> 1) + (l_min_i + FIXED_ONE - l_max), dy,
+ FIXED_BITS + TRI_FRACTION_BITS - 15);
+ ADD_COVERAGE(coverage, cf);
+ // all pixels on the right have cf = 1.0
+ } else {
+ /*
+ * spans several pixels in one scanline
+ * l_max
+ * +--------+--/-----+ yt
+ * | |/ |
+ * | /| |
+ * | / | |
+ * +---/----+--------+ y
+ * l_min (l_min_i + TRI_ONE)
+ */
+
+ // handle the first pixel separately...
+ const int32_t y_incr = left->y_incr;
+ int32_t dx = TRI_FROM_FIXED(l_min_i - l_min) + TRI_ONE;
+ int32_t cf = (dx * dx * y_incr) >> cf_shift;
+ ADD_COVERAGE(coverage, cf);
+
+ // following pixels get covered by y_incr, but we need
+ // to fix-up the cf to account for previous partial pixel
+ dx = TRI_FROM_FIXED(l_min - l_min_i);
+ cf -= (dx * dx * y_incr) >> cf_shift;
+ for (int x = l_min_i+FIXED_ONE ; x < l_max_i-FIXED_ONE ; x += FIXED_ONE) {
+ cf += y_incr >> (TRI_ITERATORS_BITS-15);
+ ADD_COVERAGE(coverage, cf);
+ }
+
+ // and the last pixel
+ dx = TRI_FROM_FIXED(l_max - l_max_i) - TRI_ONE;
+ cf += (dx * dx * y_incr) >> cf_shift;
+ ADD_COVERAGE(coverage, cf);
+ }
+
+ // now, fill up all fully covered pixels
+ coverage = covPtr + gglFixedToIntFloor(l_max_i);
+ int cf = ((y - yt) << (15 - TRI_FRACTION_BITS));
+ if (ggl_likely(cf >= 0x8000)) {
+ SET_COVERAGE(coverage, 0x7FFF, ((r_max - l_max_i)>>FIXED_BITS)+1);
+ } else {
+ for (int x=l_max_i ; x<r_max ; x+=FIXED_ONE) {
+ ADD_COVERAGE(coverage, cf);
+ }
+ }
+
+ // subtract the coverage of the right edge
+ coverage = covPtr + gglFixedToIntFloor(r_min_i);
+ if (r_min_i == gglFloorx(r_max)) {
+ GGLfixed dx = r_max - r_min;
+ int32_t dy = y - yt;
+ int cf = gglMulx((dx >> 1) + (r_min_i + FIXED_ONE - r_max), dy,
+ FIXED_BITS + TRI_FRACTION_BITS - 15);
+ SUB_COVERAGE(coverage, cf);
+ // all pixels on the right have cf = 1.0
+ } else {
+ // handle the first pixel separately...
+ const int32_t y_incr = right->y_incr;
+ int32_t dx = TRI_FROM_FIXED(r_min_i - r_min) + TRI_ONE;
+ int32_t cf = (dx * dx * y_incr) >> cf_shift;
+ SUB_COVERAGE(coverage, cf);
+
+ // following pixels get covered by y_incr, but we need
+ // to fix-up the cf to account for previous partial pixel
+ dx = TRI_FROM_FIXED(r_min - r_min_i);
+ cf -= (dx * dx * y_incr) >> cf_shift;
+ for (int x = r_min_i+FIXED_ONE ; x < r_max_i-FIXED_ONE ; x += FIXED_ONE) {
+ cf += y_incr >> (TRI_ITERATORS_BITS-15);
+ SUB_COVERAGE(coverage, cf);
+ }
+
+ // and the last pixel
+ dx = TRI_FROM_FIXED(r_max - r_max_i) - TRI_ONE;
+ cf += (dx * dx * y_incr) >> cf_shift;
+ SUB_COVERAGE(coverage, cf);
+ }
+
+ // did we reach the end of an edge? if so, get a new one.
+ if (y == left->y_bot || y == right->y_bot) {
+ // bail out if we're done
+ if (i>=num_edges)
+ break;
+ if (y == left->y_bot)
+ left = &edges[i++];
+ if (y == right->y_bot)
+ right = &edges[i++];
+ }
+
+ // next scanline
+ yt = y;
+
+ // did we just finish a scanline?
+ retire = (y << (32-TRI_FRACTION_BITS)) == 0;
+ } while (true);
+
+ // render the last scanline
+ if (c->iterators.xl < c->iterators.xr)
+ c->scanline(c);
+}
+
+}; // namespace android
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-25 17:00:13 +0000