Simplify olivec_triangle() and olivec_triangle3c() implementations

olive.c

@@ -574,7 +574,7 @@ OLIVECDEF void olivec_line(Olivec_Canvas oc, int x1, int y1, int x2, int y2, uin
     }
 }
 
-OLIVECDEF uint32_t mix_colors3(uint32_t c1, uint32_t c2, uint32_t c3, int t1, int t2, int t3, int den)
+OLIVECDEF uint32_t mix_colors3(uint32_t c1, uint32_t c2, uint32_t c3, int u1, int u2, int det)
 {
     // TODO: estimate how much overflows are an issue in integer only environment
     int64_t r1 = OLIVEC_RED(c1);
@@ -592,11 +592,12 @@ OLIVECDEF uint32_t mix_colors3(uint32_t c1, uint32_t c2, uint32_t c3, int t1, in
     int64_t b3 = OLIVEC_BLUE(c3);
     int64_t a3 = OLIVEC_ALPHA(c3);
 
-    if (den != 0) {
-        int64_t r4 = (r1*t1 + r2*t2 + r3*t3)/den;
-        int64_t g4 = (g1*t1 + g2*t2 + g3*t3)/den;
-        int64_t b4 = (b1*t1 + b2*t2 + b3*t3)/den;
-        int64_t a4 = (a1*t1 + a2*t2 + a3*t3)/den;
+    if (det != 0) {
+        int u3 = det - u1 - u2;
+        int64_t r4 = (r1*u1 + r2*u2 + r3*u3)/det;
+        int64_t g4 = (g1*u1 + g2*u2 + g3*u3)/det;
+        int64_t b4 = (b1*u1 + b2*u2 + b3*u3)/det;
+        int64_t a4 = (a1*u1 + a2*u2 + a3*u3)/det;
 
         return OLIVEC_RGBA(r4, g4, b4, a4);
     }
@@ -617,62 +618,14 @@ OLIVECDEF void barycentric(int x1, int y1, int x2, int y2, int x3, int y3,
 OLIVECDEF void olivec_triangle3c(Olivec_Canvas oc, int x1, int y1, int x2, int y2, int x3, int y3,
                                  uint32_t c1, uint32_t c2, uint32_t c3)
 {
-    if (y1 > y2) {
-        OLIVEC_SWAP(int, x1, x2);
-        OLIVEC_SWAP(int, y1, y2);
-        OLIVEC_SWAP(int, c1, c2);
-    }
-
-    if (y2 > y3) {
-        OLIVEC_SWAP(int, x2, x3);
-        OLIVEC_SWAP(int, y2, y3);
-        OLIVEC_SWAP(int, c2, c3);
-    }
-
-    if (y1 > y2) {
-        OLIVEC_SWAP(int, x1, x2);
-        OLIVEC_SWAP(int, y1, y2);
-        OLIVEC_SWAP(int, c1, c2);
-    }
-
-    int dx12 = x2 - x1;
-    int dy12 = y2 - y1;
-    int dx13 = x3 - x1;
-    int dy13 = y3 - y1;
-
-    for (int y = y1; y <= y2; ++y) {
-        // TODO: move boundary checks outside of loops in olivec_fill_triangle
-        if (0 <= y && (size_t) y < oc.height) {
-            int s1 = dy12 != 0 ? (y - y1)*dx12/dy12 + x1 : x1;
-            int s2 = dy13 != 0 ? (y - y1)*dx13/dy13 + x1 : x1;
-            if (s1 > s2) OLIVEC_SWAP(int, s1, s2);
-            for (int x = s1; x <= s2; ++x) {
-                if (0 <= x && (size_t) x < oc.width) {
-                    int u1, u2, det;
-                    barycentric(x1, y1, x2, y2, x3, y3, x, y, &u1, &u2, &det);
-                    uint32_t color = mix_colors3(c1, c2, c3, u1, u2, det - u1 - u2, det);
-                    olivec_blend_color(&OLIVEC_PIXEL(oc, x, y), color);
-                }
-            }
-        }
-    }
-
-    int dx32 = x2 - x3;
-    int dy32 = y2 - y3;
-    int dx31 = x1 - x3;
-    int dy31 = y1 - y3;
-
-    for (int y = y2; y <= y3; ++y) {
-        if (0 <= y && (size_t) y < oc.height) {
-            int s1 = dy32 != 0 ? (y - y3)*dx32/dy32 + x3 : x3;
-            int s2 = dy31 != 0 ? (y - y3)*dx31/dy31 + x3 : x3;
-            if (s1 > s2) OLIVEC_SWAP(int, s1, s2);
-            for (int x = s1; x <= s2; ++x) {
-                if (0 <= x && (size_t) x < oc.width) {
+    Olivec_Tri tri = olivec_tri_new(x1, y1, x2, y2, x3, y3);
+    if (olivec_tri_vert(&tri, oc.height, &y1, &y2)) {
+        for (int y = y1; y <= y2; ++y) {
+            if (olivec_tri_horz(&tri, oc.width, y, &x1, &x2)) {
+                for (int x = x1; x <= x2; ++x) {
                     int u1, u2, det;
-                    barycentric(x1, y1, x2, y2, x3, y3, x, y, &u1, &u2, &det);
-                    uint32_t color = mix_colors3(c1, c2, c3, u1, u2, det - u1 - u2, det);
-                    olivec_blend_color(&OLIVEC_PIXEL(oc, x, y), color);
+                    olivec_tri_bary(&tri, x, y, &u1, &u2, &det);
+                    olivec_blend_color(&OLIVEC_PIXEL(oc, x, y), mix_colors3(c1, c2, c3, u1, u2, det));
                 }
             }
         }
@@ -784,9 +737,9 @@ OLIVECDEF void olivec_triangle3uv(Olivec_Canvas oc, int x1, int y1, int x2, int
                     int u3 = det - u1 - u2;
                     float z = z1*u1/det + z2*u2/det + z3*(det - u1 - u2)/det;
                     Uv uv = olivec_uv(
-                        uv1.u*u1/det + uv2.u*u2/det + uv3.u*u3/det,
-                        uv1.v*u1/det + uv2.v*u2/det + uv3.v*u3/det
-                    );
+                                uv1.u*u1/det + uv2.u*u2/det + uv3.u*u3/det,
+                                uv1.v*u1/det + uv2.v*u2/det + uv3.v*u3/det
+                            );
                     int texture_x = uv.u/z*texture.width;
                     if (texture_x < 0) texture_x = 0;
                     if ((size_t) texture_x >= texture.width) texture_x = texture.width - 1;
@@ -816,9 +769,9 @@ OLIVECDEF void olivec_triangle3uv(Olivec_Canvas oc, int x1, int y1, int x2, int
                     int u3 = det - u1 - u2;
                     float z = z1*u1/det + z2*u2/det + z3*(det - u1 - u2)/det;
                     Uv uv = olivec_uv(
-                        uv1.u*u1/det + uv2.u*u2/det + uv3.u*u3/det,
-                        uv1.v*u1/det + uv2.v*u2/det + uv3.v*u3/det
-                    );
+                                uv1.u*u1/det + uv2.u*u2/det + uv3.u*u3/det,
+                                uv1.v*u1/det + uv2.v*u2/det + uv3.v*u3/det
+                            );
                     int texture_x = uv.u/z*texture.width;
                     if (texture_x < 0) texture_x = 0;
                     if ((size_t) texture_x >= texture.width) texture_x = texture.width - 1;
@@ -835,52 +788,11 @@ OLIVECDEF void olivec_triangle3uv(Olivec_Canvas oc, int x1, int y1, int x2, int
 // TODO: AA for triangle
 OLIVECDEF void olivec_triangle(Olivec_Canvas oc, int x1, int y1, int x2, int y2, int x3, int y3, uint32_t color)
 {
-    if (y1 > y2) {
-        OLIVEC_SWAP(int, x1, x2);
-        OLIVEC_SWAP(int, y1, y2);
-    }
-
-    if (y2 > y3) {
-        OLIVEC_SWAP(int, x2, x3);
-        OLIVEC_SWAP(int, y2, y3);
-    }
-
-    if (y1 > y2) {
-        OLIVEC_SWAP(int, x1, x2);
-        OLIVEC_SWAP(int, y1, y2);
-    }
-
-    int dx12 = x2 - x1;
-    int dy12 = y2 - y1;
-    int dx13 = x3 - x1;
-    int dy13 = y3 - y1;
-
-    for (int y = y1; y <= y2; ++y) {
-        // TODO: move boundary checks outside of loops in olivec_fill_triangle
-        if (0 <= y && (size_t) y < oc.height) {
-            int s1 = dy12 != 0 ? (y - y1)*dx12/dy12 + x1 : x1;
-            int s2 = dy13 != 0 ? (y - y1)*dx13/dy13 + x1 : x1;
-            if (s1 > s2) OLIVEC_SWAP(int, s1, s2);
-            for (int x = s1; x <= s2; ++x) {
-                if (0 <= x && (size_t) x < oc.width) {
-                    olivec_blend_color(&OLIVEC_PIXEL(oc, x, y), color);
-                }
-            }
-        }
-    }
-
-    int dx32 = x2 - x3;
-    int dy32 = y2 - y3;
-    int dx31 = x1 - x3;
-    int dy31 = y1 - y3;
-
-    for (int y = y2; y <= y3; ++y) {
-        if (0 <= y && (size_t) y < oc.height) {
-            int s1 = dy32 != 0 ? (y - y3)*dx32/dy32 + x3 : x3;
-            int s2 = dy31 != 0 ? (y - y3)*dx31/dy31 + x3 : x3;
-            if (s1 > s2) OLIVEC_SWAP(int, s1, s2);
-            for (int x = s1; x <= s2; ++x) {
-                if (0 <= x && (size_t) x < oc.width) {
+    Olivec_Tri tri = olivec_tri_new(x1, y1, x2, y2, x3, y3);
+    if (olivec_tri_vert(&tri, oc.height, &y1, &y2)) {
+        for (int y = y1; y <= y2; ++y) {
+            if (olivec_tri_horz(&tri, oc.width, y, &x1, &x2)) {
+                for (int x = x1; x <= x2; ++x) {
                     olivec_blend_color(&OLIVEC_PIXEL(oc, x, y), color);
                 }
             }
@@ -917,8 +829,10 @@ OLIVECDEF void olivec_sprite_blend(Olivec_Canvas oc, int x, int y, int w, int h,
     Olivec_Normalized_Rect nr = {0};
     if (!olivec_normalize_rect(x, y, w, h, oc.width, oc.height, &nr)) return;
 
-    int xa = nr.ox1; if (w < 0) xa = nr.ox2;
-    int ya = nr.oy1; if (h < 0) ya = nr.oy2;
+    int xa = nr.ox1;
+    if (w < 0) xa = nr.ox2;
+    int ya = nr.oy1;
+    if (h < 0) ya = nr.oy2;
     for (int y = nr.y1; y <= nr.y2; ++y) {
         for (int x = nr.x1; x <= nr.x2; ++x) {
             size_t nx = (x - xa)*((int) sprite.width)/w;
@@ -936,8 +850,10 @@ OLIVECDEF void olivec_sprite_copy(Olivec_Canvas oc, int x, int y, int w, int h,
     Olivec_Normalized_Rect nr = {0};
     if (!olivec_normalize_rect(x, y, w, h, oc.width, oc.height, &nr)) return;
 
-    int xa = nr.ox1; if (w < 0) xa = nr.ox2;
-    int ya = nr.oy1; if (h < 0) ya = nr.oy2;
+    int xa = nr.ox1;
+    if (w < 0) xa = nr.ox2;
+    int ya = nr.oy1;
+    if (h < 0) ya = nr.oy2;
     for (int y = nr.y1; y <= nr.y2; ++y) {
         for (int x = nr.x1; x <= nr.x2; ++x) {
             size_t nx = (x - xa)*((int) sprite.width)/w;
@@ -958,27 +874,32 @@ OLIVECDEF Uv olivec_uv(float u, float v)
 Olivec_Tri olivec_tri_new(int x1, int y1, int x2, int y2, int x3, int y3)
 {
     Olivec_Tri tri = {
-        .order = {0, 1, 2},
         .xs = {x1, x2, x3},
         .ys = {y1, y2, y3},
     };
 
+    int order[3] = {0, 1, 2};
+
     if (tri.ys[0] > tri.ys[1]) {
         OLIVEC_SWAP(int, tri.xs[0], tri.xs[1]);
         OLIVEC_SWAP(int, tri.ys[0], tri.ys[1]);
-        OLIVEC_SWAP(int, tri.order[0], tri.order[1]);
+        OLIVEC_SWAP(int, order[0], order[1]);
     }
 
     if (tri.ys[1] > tri.ys[2]) {
         OLIVEC_SWAP(int, tri.xs[1], tri.xs[2]);
         OLIVEC_SWAP(int, tri.ys[1], tri.ys[2]);
-        OLIVEC_SWAP(int, tri.order[1], tri.order[2]);
+        OLIVEC_SWAP(int, order[1], order[2]);
     }
 
     if (tri.ys[0] > tri.ys[1]) {
         OLIVEC_SWAP(int, tri.xs[0], tri.xs[1]);
         OLIVEC_SWAP(int, tri.ys[0], tri.ys[1]);
-        OLIVEC_SWAP(int, tri.order[0], tri.order[1]);
+        OLIVEC_SWAP(int, order[0], order[1]);
+    }
+
+    for (int i = 0; i < 3; ++i) {
+        tri.order[order[i]] = i;
     }
 
     return tri;
@@ -1006,7 +927,7 @@ bool olivec_tri_horz(Olivec_Tri *tri, size_t width, int y, int *s1, int *s2)
     int y2 = tri->ys[1];
     int y3 = tri->ys[2];
 
-    if (y1 <= y && y < y2) {
+    if (y1 <= y && y <= y2) {
         // upper triangle
         int dx12 = x2 - x1;
         int dy12 = y2 - y1;
@@ -1014,7 +935,7 @@ bool olivec_tri_horz(Olivec_Tri *tri, size_t width, int y, int *s1, int *s2)
         int dy13 = y3 - y1;
         *s1 = dy12 != 0 ? (y - y1)*dx12/dy12 + x1 : x1;
         *s2 = dy13 != 0 ? (y - y1)*dx13/dy13 + x1 : x1;
-    } else if (y2 <= y && y <= y3) {
+    } else if (y2 < y && y <= y3) {
         // bottom triangle
         int dx32 = x2 - x3;
         int dy32 = y2 - y3;

viewobj.c

@@ -254,7 +254,7 @@ int main(void)
                         float z = 1/v1.z*u1/det + 1/v2.z*u2/det + 1/v3.z*(det - u1 - u2)/det;
                         if (z > zbuffer[y*WIDTH + x]) {
                             zbuffer[y*WIDTH + x] = z;
-                            OLIVEC_PIXEL(oc, x, y) = mix_colors3(0xFF1818FF, 0xFF18FF18, 0xFFFF1818, u1, u2, det - u1 - u2, det);
+                            OLIVEC_PIXEL(oc, x, y) = mix_colors3(0xFF1818FF, 0xFF18FF18, 0xFFFF1818, u1, u2, det);
 
                             z = 1.0f/z;
                             if (z >= 1.0) {
@@ -270,7 +270,7 @@ int main(void)
         }
     }
 
-    const char *file_path = "tri.png";
+    const char *file_path = "teapot.png";
     if (!stbi_write_png(file_path, WIDTH, HEIGHT, 4, pixels, sizeof(uint32_t)*WIDTH)) {
         fprintf(stderr, "ERROR: could not write file %s\n", file_path);
         return_defer(1);