From 7d3e8d14140f8654f31aa7ac78649d89f8f88659 Mon Sep 17 00:00:00 2001 From: Magnus Norddahl Date: Tue, 8 Nov 2016 23:08:25 +0100 Subject: [PATCH] Fix triangle drawer clipping bug --- src/r_poly_triangle.cpp | 139 +++++++++++++++++++++++++++------------- src/r_poly_triangle.h | 2 +- src/r_triangle.cpp | 135 +++++++++++++++++++++++++------------- src/r_triangle.h | 2 +- 4 files changed, 190 insertions(+), 88 deletions(-) diff --git a/src/r_poly_triangle.cpp b/src/r_poly_triangle.cpp index ffb8d82bb..34bc74dca 100644 --- a/src/r_poly_triangle.cpp +++ b/src/r_poly_triangle.cpp @@ -36,6 +36,10 @@ #include "r_data/colormaps.h" #include "r_poly_triangle.h" +#ifndef NO_SSE +#include +#endif + void PolyTriangleDrawer::draw(const TriUniforms &uniforms, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, int cliptop, int clipbottom, FTexture *texture) { if (r_swtruecolor) @@ -124,10 +128,8 @@ void PolyTriangleDrawer::draw_shaded_triangle(const TriVertex *vert, bool ccw, S { // Cull, clip and generate additional vertices as needed TriVertex clippedvert[6]; - int numclipvert = 0; - clipedge(vert[0], vert[1], clippedvert, numclipvert); - clipedge(vert[1], vert[2], clippedvert, numclipvert); - clipedge(vert[2], vert[0], clippedvert, numclipvert); + int numclipvert; + clipedge(vert, clippedvert, numclipvert); // Map to 2D viewport: for (int j = 0; j < numclipvert; j++) @@ -170,62 +172,113 @@ void PolyTriangleDrawer::draw_shaded_triangle(const TriVertex *vert, bool ccw, S bool PolyTriangleDrawer::cullhalfspace(float clipdistance1, float clipdistance2, float &t1, float &t2) { - float d1 = clipdistance1 * (1.0f - t1) + clipdistance2 * t1; - float d2 = clipdistance1 * (1.0f - t2) + clipdistance2 * t2; - if (d1 < 0.0f && d2 < 0.0f) + if (clipdistance1 < 0.0f && clipdistance2 < 0.0f) return true; - if (d1 < 0.0f) - t1 = MAX(-clipdistance1 / (clipdistance2 - clipdistance1), t1); + if (clipdistance1 < 0.0f) + t1 = MAX(-clipdistance1 / (clipdistance2 - clipdistance1), 0.0f); + else + t1 = 0.0f; - if (d2 < 0.0f) - t2 = MIN(1.0f + clipdistance2 / (clipdistance1 - clipdistance2), t2); + if (clipdistance2 < 0.0f) + t2 = MIN(1.0f + clipdistance2 / (clipdistance1 - clipdistance2), 1.0f); + else + t2 = 1.0f; return false; } -void PolyTriangleDrawer::clipedge(const TriVertex &v1, const TriVertex &v2, TriVertex *clippedvert, int &numclipvert) +void PolyTriangleDrawer::clipedge(const TriVertex *verts, TriVertex *clippedvert, int &numclipvert) { // Clip and cull so that the following is true for all vertices: // -v.w <= v.x <= v.w // -v.w <= v.y <= v.w // -v.w <= v.z <= v.w - - float t1 = 0.0f, t2 = 1.0f; - bool culled = - cullhalfspace(v1.x + v1.w, v2.x + v2.w, t1, t2) || - cullhalfspace(v1.w - v1.x, v2.w - v2.x, t1, t2) || - cullhalfspace(v1.y + v1.w, v2.y + v2.w, t1, t2) || - cullhalfspace(v1.w - v1.y, v2.w - v2.y, t1, t2) || - cullhalfspace(v1.z + v1.w, v2.z + v2.w, t1, t2) || - cullhalfspace(v1.w - v1.z, v2.w - v2.z, t1, t2); - if (culled) - return; - - if (t1 == 0.0f) + + // use barycentric weights while clipping vertices + float weights[6 * 3 * 2]; + for (int i = 0; i < 3; i++) { - clippedvert[numclipvert++] = v1; + weights[i * 3 + 0] = 0.0f; + weights[i * 3 + 1] = 0.0f; + weights[i * 3 + 2] = 0.0f; + weights[i * 3 + i] = 1.0f; } - else + + // halfspace clip distances + float clipdistance[6 * 3]; + for (int i = 0; i < 3; i++) { - auto &v = clippedvert[numclipvert++]; - v.x = v1.x * (1.0f - t1) + v2.x * t1; - v.y = v1.y * (1.0f - t1) + v2.y * t1; - v.z = v1.z * (1.0f - t1) + v2.z * t1; - v.w = v1.w * (1.0f - t1) + v2.w * t1; - for (int i = 0; i < TriVertex::NumVarying; i++) - v.varying[i] = v1.varying[i] * (1.0f - t1) + v2.varying[i] * t1; + const auto &v = verts[i]; + clipdistance[i * 6 + 0] = v.x + v.w; + clipdistance[i * 6 + 1] = v.w - v.x; + clipdistance[i * 6 + 2] = v.y + v.w; + clipdistance[i * 6 + 3] = v.w - v.y; + clipdistance[i * 6 + 4] = v.z + v.w; + clipdistance[i * 6 + 5] = v.w - v.z; } - - if (t2 != 1.0f) + + // Clip against each halfspace + float *input = weights; + float *output = weights + 6 * 3; + int inputverts = 3; + int outputverts = 0; + for (int p = 0; p < 6; p++) { - auto &v = clippedvert[numclipvert++]; - v.x = v1.x * (1.0f - t2) + v2.x * t2; - v.y = v1.y * (1.0f - t2) + v2.y * t2; - v.z = v1.z * (1.0f - t2) + v2.z * t2; - v.w = v1.w * (1.0f - t2) + v2.w * t2; - for (int i = 0; i < TriVertex::NumVarying; i++) - v.varying[i] = v1.varying[i] * (1.0f - t2) + v2.varying[i] * t2; + // Clip each edge + outputverts = 0; + for (int i = 0; i < inputverts; i++) + { + int j = (i + 1) % inputverts; + float clipdistance1 = + clipdistance[0 * 6 + p] * input[i * 3 + 0] + + clipdistance[1 * 6 + p] * input[i * 3 + 1] + + clipdistance[2 * 6 + p] * input[i * 3 + 2]; + + float clipdistance2 = + clipdistance[0 * 6 + p] * input[j * 3 + 0] + + clipdistance[1 * 6 + p] * input[j * 3 + 1] + + clipdistance[2 * 6 + p] * input[j * 3 + 2]; + + float t1, t2; + if (!cullhalfspace(clipdistance1, clipdistance2, t1, t2)) + { + // add t1 vertex + for (int k = 0; k < 3; k++) + output[outputverts * 3 + k] = input[i * 3 + k] * (1.0f - t1) + input[j * 3 + k] * t1; + outputverts++; + + if (t2 != 1.0f && t2 > t1) + { + // add t2 vertex + for (int k = 0; k < 3; k++) + output[outputverts * 3 + k] = input[i * 3 + k] * (1.0f - t2) + input[j * 3 + k] * t2; + outputverts++; + } + } + } + std::swap(input, output); + std::swap(inputverts, outputverts); + if (inputverts == 0) + break; + } + + // Convert barycentric weights to actual vertices + numclipvert = inputverts; + for (int i = 0; i < numclipvert; i++) + { + auto &v = clippedvert[i]; + memset(&v, 0, sizeof(TriVertex)); + for (int w = 0; w < 3; w++) + { + float weight = input[i * 3 + w]; + v.x += verts[w].x * weight; + v.y += verts[w].y * weight; + v.z += verts[w].z * weight; + v.w += verts[w].w * weight; + for (int iv = 0; iv < TriVertex::NumVarying; iv++) + v.varying[iv] += verts[w].varying[iv] * weight; + } } } diff --git a/src/r_poly_triangle.h b/src/r_poly_triangle.h index cba5202b7..79c8d4a7a 100644 --- a/src/r_poly_triangle.h +++ b/src/r_poly_triangle.h @@ -39,7 +39,7 @@ private: static void draw_arrays(const TriUniforms &uniforms, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, int cliptop, int clipbottom, const uint8_t *texturePixels, int textureWidth, int textureHeight, int solidcolor, DrawerThread *thread, void(*drawfunc)(const ScreenPolyTriangleDrawerArgs *, DrawerThread *)); static void draw_shaded_triangle(const TriVertex *vertices, bool ccw, ScreenPolyTriangleDrawerArgs *args, DrawerThread *thread, void(*drawfunc)(const ScreenPolyTriangleDrawerArgs *, DrawerThread *)); static bool cullhalfspace(float clipdistance1, float clipdistance2, float &t1, float &t2); - static void clipedge(const TriVertex &v1, const TriVertex &v2, TriVertex *clippedvert, int &numclipvert); + static void clipedge(const TriVertex *verts, TriVertex *clippedvert, int &numclipvert); static void queue_arrays(const TriUniforms &uniforms, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, int cliptop, int clipbottom, const uint8_t *texturePixels, int textureWidth, int textureHeight, int solidcolor); diff --git a/src/r_triangle.cpp b/src/r_triangle.cpp index 95e4e636e..340306fec 100644 --- a/src/r_triangle.cpp +++ b/src/r_triangle.cpp @@ -139,10 +139,8 @@ void TriangleDrawer::draw_shaded_triangle(const TriVertex *vert, bool ccw, Scree { // Cull, clip and generate additional vertices as needed TriVertex clippedvert[6]; - int numclipvert = 0; - clipedge(vert[0], vert[1], clippedvert, numclipvert); - clipedge(vert[1], vert[2], clippedvert, numclipvert); - clipedge(vert[2], vert[0], clippedvert, numclipvert); + int numclipvert; + clipedge(vert, clippedvert, numclipvert); // Map to 2D viewport: for (int j = 0; j < numclipvert; j++) @@ -185,62 +183,113 @@ void TriangleDrawer::draw_shaded_triangle(const TriVertex *vert, bool ccw, Scree bool TriangleDrawer::cullhalfspace(float clipdistance1, float clipdistance2, float &t1, float &t2) { - float d1 = clipdistance1 * (1.0f - t1) + clipdistance2 * t1; - float d2 = clipdistance1 * (1.0f - t2) + clipdistance2 * t2; - if (d1 < 0.0f && d2 < 0.0f) + if (clipdistance1 < 0.0f && clipdistance2 < 0.0f) return true; - if (d1 < 0.0f) - t1 = MAX(-clipdistance1 / (clipdistance2 - clipdistance1), t1); + if (clipdistance1 < 0.0f) + t1 = MAX(-clipdistance1 / (clipdistance2 - clipdistance1), 0.0f); + else + t1 = 0.0f; - if (d2 < 0.0f) - t2 = MIN(1.0f + clipdistance2 / (clipdistance1 - clipdistance2), t2); + if (clipdistance2 < 0.0f) + t2 = MIN(1.0f + clipdistance2 / (clipdistance1 - clipdistance2), 1.0f); + else + t2 = 1.0f; return false; } -void TriangleDrawer::clipedge(const TriVertex &v1, const TriVertex &v2, TriVertex *clippedvert, int &numclipvert) +void TriangleDrawer::clipedge(const TriVertex *verts, TriVertex *clippedvert, int &numclipvert) { // Clip and cull so that the following is true for all vertices: // -v.w <= v.x <= v.w // -v.w <= v.y <= v.w // -v.w <= v.z <= v.w - - float t1 = 0.0f, t2 = 1.0f; - bool culled = - cullhalfspace(v1.x + v1.w, v2.x + v2.w, t1, t2) || - cullhalfspace(v1.w - v1.x, v2.w - v2.x, t1, t2) || - cullhalfspace(v1.y + v1.w, v2.y + v2.w, t1, t2) || - cullhalfspace(v1.w - v1.y, v2.w - v2.y, t1, t2) || - cullhalfspace(v1.z + v1.w, v2.z + v2.w, t1, t2) || - cullhalfspace(v1.w - v1.z, v2.w - v2.z, t1, t2); - if (culled) - return; - - if (t1 == 0.0f) + + // use barycentric weights while clipping vertices + float weights[6 * 3 * 2]; + for (int i = 0; i < 3; i++) { - clippedvert[numclipvert++] = v1; + weights[i * 3 + 0] = 0.0f; + weights[i * 3 + 1] = 0.0f; + weights[i * 3 + 2] = 0.0f; + weights[i * 3 + i] = 1.0f; } - else + + // halfspace clip distances + float clipdistance[6 * 3]; + for (int i = 0; i < 3; i++) { - auto &v = clippedvert[numclipvert++]; - v.x = v1.x * (1.0f - t1) + v2.x * t1; - v.y = v1.y * (1.0f - t1) + v2.y * t1; - v.z = v1.z * (1.0f - t1) + v2.z * t1; - v.w = v1.w * (1.0f - t1) + v2.w * t1; - for (int i = 0; i < TriVertex::NumVarying; i++) - v.varying[i] = v1.varying[i] * (1.0f - t1) + v2.varying[i] * t1; + const auto &v = verts[i]; + clipdistance[i * 6 + 0] = v.x + v.w; + clipdistance[i * 6 + 1] = v.w - v.x; + clipdistance[i * 6 + 2] = v.y + v.w; + clipdistance[i * 6 + 3] = v.w - v.y; + clipdistance[i * 6 + 4] = v.z + v.w; + clipdistance[i * 6 + 5] = v.w - v.z; } - - if (t2 != 1.0f) + + // Clip against each halfspace + float *input = weights; + float *output = weights + 6 * 3; + int inputverts = 3; + int outputverts = 0; + for (int p = 0; p < 6; p++) { - auto &v = clippedvert[numclipvert++]; - v.x = v1.x * (1.0f - t2) + v2.x * t2; - v.y = v1.y * (1.0f - t2) + v2.y * t2; - v.z = v1.z * (1.0f - t2) + v2.z * t2; - v.w = v1.w * (1.0f - t2) + v2.w * t2; - for (int i = 0; i < TriVertex::NumVarying; i++) - v.varying[i] = v1.varying[i] * (1.0f - t2) + v2.varying[i] * t2; + // Clip each edge + outputverts = 0; + for (int i = 0; i < inputverts; i++) + { + int j = (i + 1) % inputverts; + float clipdistance1 = + clipdistance[0 * 6 + p] * input[i * 3 + 0] + + clipdistance[1 * 6 + p] * input[i * 3 + 1] + + clipdistance[2 * 6 + p] * input[i * 3 + 2]; + + float clipdistance2 = + clipdistance[0 * 6 + p] * input[j * 3 + 0] + + clipdistance[1 * 6 + p] * input[j * 3 + 1] + + clipdistance[2 * 6 + p] * input[j * 3 + 2]; + + float t1, t2; + if (!cullhalfspace(clipdistance1, clipdistance2, t1, t2)) + { + // add t1 vertex + for (int k = 0; k < 3; k++) + output[outputverts * 3 + k] = input[i * 3 + k] * (1.0f - t1) + input[j * 3 + k] * t1; + outputverts++; + + if (t2 != 1.0f && t2 > t1) + { + // add t2 vertex + for (int k = 0; k < 3; k++) + output[outputverts * 3 + k] = input[i * 3 + k] * (1.0f - t2) + input[j * 3 + k] * t2; + outputverts++; + } + } + } + std::swap(input, output); + std::swap(inputverts, outputverts); + if (inputverts == 0) + break; + } + + // Convert barycentric weights to actual vertices + numclipvert = inputverts; + for (int i = 0; i < numclipvert; i++) + { + auto &v = clippedvert[i]; + memset(&v, 0, sizeof(TriVertex)); + for (int w = 0; w < 3; w++) + { + float weight = input[i * 3 + w]; + v.x += verts[w].x * weight; + v.y += verts[w].y * weight; + v.z += verts[w].z * weight; + v.w += verts[w].w * weight; + for (int iv = 0; iv < TriVertex::NumVarying; iv++) + v.varying[iv] += verts[w].varying[iv] * weight; + } } } diff --git a/src/r_triangle.h b/src/r_triangle.h index 254cb5570..82b1d2c4d 100644 --- a/src/r_triangle.h +++ b/src/r_triangle.h @@ -102,7 +102,7 @@ private: static void draw_arrays(const TriUniforms &uniforms, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, const uint8_t *texturePixels, int textureWidth, int textureHeight, int solidcolor, DrawerThread *thread, void(*drawfunc)(const ScreenTriangleDrawerArgs *, DrawerThread *)); static void draw_shaded_triangle(const TriVertex *vertices, bool ccw, ScreenTriangleDrawerArgs *args, DrawerThread *thread, void(*drawfunc)(const ScreenTriangleDrawerArgs *, DrawerThread *)); static bool cullhalfspace(float clipdistance1, float clipdistance2, float &t1, float &t2); - static void clipedge(const TriVertex &v1, const TriVertex &v2, TriVertex *clippedvert, int &numclipvert); + static void clipedge(const TriVertex *verts, TriVertex *clippedvert, int &numclipvert); static void queue_arrays(const TriUniforms &uniforms, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, const uint8_t *texturePixels, int textureWidth, int textureHeight, int solidcolor);