From 90ce80341ee477019c134f437fbe57a7161c1026 Mon Sep 17 00:00:00 2001 From: kkard2 Date: Wed, 10 Sep 2025 19:44:38 +0200 Subject: Revert "this does not work" This reverts commit 0d49525bf0bd1d50c436a50000384926a82df972. --- sponge.h | 156 +++++++-------------------------------------------------------- 1 file changed, 17 insertions(+), 139 deletions(-) diff --git a/sponge.h b/sponge.h index 78bfadc..02f1bcd 100644 --- a/sponge.h +++ b/sponge.h @@ -41,9 +41,6 @@ void sponge_draw_triangle_col3( #define SPONGE__MAX(x, y) ((x) > (y) ? (x) : (y)) #define SPONGE__ABS(x) ((x) >= 0 ? (x) : -(x)) -// NOTE(kard): there are "better" macros that don't need a type, but this is simpler -#define SPONGE__SWAP(x, y, T) { T SPONGE__SWAP_temp = x; y = x; x = SPONGE__SWAP_temp; } - typedef struct { float a; float r; @@ -182,14 +179,13 @@ void sponge_draw_line(sponge_Texture c, int32_t x0, int32_t y0, int32_t x1, int3 dx = SPONGE__ABS(dx); int32_t dy = y1 - y0; dy = SPONGE__ABS(dy); + int32_t d = (2 * dy) - dx; int32_t sx = (x0 < x1) ? 1 : -1; int32_t sy = (y0 < y1) ? 1 : -1; int32_t err = dx - dy; while (1) { - // TODO(kard): "preprocess" line for this check to not be necessary - // actually idk what is faster and how much line needs to be outside, check if (x0 >= 0 && x0 < (int32_t)c.width && y0 >= 0 && y0 < (int32_t)c.height) c.pixels[(y0 * c.stride) + x0] = color; @@ -229,7 +225,7 @@ void sponge_draw_triangle_col(sponge_Texture c, int32_t x0, int32_t y0, int32_t // NOTE(kard): // this does not accept floats on purpose. // there are more efficient algorithms for producing triangle pixels other than -// checking every one of them in rectangle with barycentric coords (e.g. using Bresenham algorithm) +// checking every one of them in rectangle with barycentric coords (e.g. using Brehensam algorithm) // and they can work with integer coordinates. // TODO(kard): this should be explored in the future // TODO(kard): backface culling? @@ -238,23 +234,6 @@ void sponge_draw_triangle_col3( uint32_t color0, uint32_t color1, uint32_t color2) { SPONGE_ASSERT(sponge_canvas_valid(c)); - // order triangle so y0 <= y1 <= y2 - if (y0 > y1) { - SPONGE__SWAP(x0, x1, int32_t); - SPONGE__SWAP(y0, y1, int32_t); - SPONGE__SWAP(color0, color1, uint32_t); - } - if (y1 > y2) { - SPONGE__SWAP(x1, x2, int32_t); - SPONGE__SWAP(y1, y2, int32_t); - SPONGE__SWAP(color1, color2, uint32_t); - if (y0 > y1) { - SPONGE__SWAP(x0, x1, int32_t); - SPONGE__SWAP(y0, y1, int32_t); - SPONGE__SWAP(color0, color1, uint32_t); - } - } - sponge_Vec2 t0 = { .x = (float)x0, .y = (float)y0 }; sponge_Vec2 t1 = { .x = (float)x1, .y = (float)y1 }; sponge_Vec2 t2 = { .x = (float)x2, .y = (float)y2 }; @@ -271,129 +250,28 @@ void sponge_draw_triangle_col3( sponge__BarycentricContext ctx = sponge__barycentric_init(t0, t1, t2); + uint32_t *row = c.pixels + (min_y * c.stride); + sponge__ColorF color0f = sponge__colf_unpack(color0); sponge__ColorF color1f = sponge__colf_unpack(color1); sponge__ColorF color2f = sponge__colf_unpack(color2); - // TODO(kard): there is probably a better way to do this - // also, names are actually terrible, please rewrite this at some point (i won't) - - int32_t b_x1 = x1; - int32_t b_y1 = y1; - int32_t b_x3_end; - if (y0 == y1 || y1 == y2) - b_x3_end = x1; - else - b_x3_end = (int32_t)(x0 + ((float)(y1 - y0) / (float)(y2 - y0)) * (float)(x2 - x0)); - - - for (int32_t i = 0; i < 2; i++) { - int32_t b_x0, b_y0, b_x3, b_dx0, b_dx1, b_dy, b_d0, b_d1, b_sx0, b_sx1, b_sy, b_err0, b_err1; - - // top-down, bottom of the triangle is flat - if (i == 0) { - b_x0 = x0; b_y0 = y0; - b_x3 = x0; - b_sy = 1; - // bottom-up, top of the triangle is flat - } else { - b_x0 = x2; b_y0 = y2; - b_x3 = x2; - b_sy = -1; - } - - // this line will be handled by other iteration - if (b_y0 == b_y1) - continue; - // TODO(kard): there is a single line of overlap, fix? - - b_dx0 = b_x1 - b_x0; - b_dx0 = SPONGE__ABS(b_dx0); - b_dx1 = b_x3_end - b_x0; - b_dx1 = SPONGE__ABS(b_dx1); - b_dy = b_y1 - b_y0; - b_dy = SPONGE__ABS(b_dy); - - b_d0 = (2 * b_dy) - b_dx0; - b_d1 = (2 * b_dy) - b_dx1; - - b_sx0 = (b_x0 < b_x1 ) ? 1 : -1; - b_sx1 = (b_x3 < b_x3_end) ? 1 : -1; - - b_err0 = b_dx0 - b_dy; - b_err1 = b_dx1 - b_dy; - - while (1) { - - while (1) { - int32_t b_err02 = b_err0 * 2; - if (b_err02 > -b_dy) { b_err0 -= b_dy; b_x0 += b_sx0; } - if (b_err02 < b_dx0) { b_err0 += b_dx0; break; } - } - while (1) { - int32_t b_err12 = b_err1 * 2; - if (b_err12 > -b_dy) { b_err1 -= b_dy; b_x3 += b_sx1; } - if (b_err12 < b_dx1) { b_err1 += b_dx1; break; } - } - - //if (b_y0 >= 0 && b_y0 < (int32_t)c.height) { - //if (b_x0 >= 0 && b_x0 < (int32_t)c.width) { - //c.pixels[b_y0 * c.stride + b_x0] = 0xFFFF0000; - //} - //if (b_x3 >= 0 && b_x3 < (int32_t)c.width) { - //c.pixels[b_y0 * c.stride + b_x3] = 0xFF00FF00; - //} - //} - - if (b_y0 >= 0 && b_y0 < (int32_t)c.height) { - int32_t y = b_y0; - uint32_t *row = c.pixels + (y * c.stride); - - uint32_t x_min = (uint32_t)SPONGE__MAX(0, SPONGE__MIN(b_x0, b_x3)); - uint32_t x_max = (uint32_t)SPONGE__MIN((int32_t)c.width - 1, SPONGE__MAX(b_x0, b_x3)); - for (uint32_t x = x_min; x < x_max; x++) { - float u, v, w; - sponge_Vec2 p = { .x = (float)x, .y = (float)y }; - sponge__barycentric(ctx, p, t0, t1, t2, &u, &v, &w); - sponge__ColorF c0 = sponge__colf_mul(color0f, u); - sponge__ColorF c1 = sponge__colf_mul(color1f, v); - sponge__ColorF c2 = sponge__colf_mul(color2f, w); - sponge__ColorF result = sponge__colf_add(c0, sponge__colf_add(c1, c2)); - //row[x] = 0xFFFF00FF; - row[x] = sponge__colf_pack(result); - } + for (uint32_t y = min_y; y <= max_y; y++, row += c.stride) { + for (uint32_t x = x0; x <= max_x; x++) { + float u, v, w; + sponge_Vec2 p = { .x = (float)x, .y = (float)y }; + sponge__barycentric(ctx, p, t0, t1, t2, &u, &v, &w); + if (u > 0.0f && v > 0.0f && w > 0.0f) + { + // TODO(kard): make more robust, this probably has a lot of off by 1 errors + sponge__ColorF c0 = sponge__colf_mul(color0f, u); + sponge__ColorF c1 = sponge__colf_mul(color1f, v); + sponge__ColorF c2 = sponge__colf_mul(color2f, w); + sponge__ColorF result = sponge__colf_add(c0, sponge__colf_add(c1, c2)); + row[x] = sponge__colf_pack(result); } - - - if (b_y0 == b_y1) - break; - - b_y0 += b_sy; } } - // int32_t dx = x1 - x0; - // dx = SPONGE__ABS(dx); - // int32_t dy = y1 - y0; - // dy = SPONGE__ABS(dy); - // int32_t d = (2 * dy) - dx; -// - // int32_t sx = (x0 < x1) ? 1 : -1; - // int32_t sy = (y0 < y1) ? 1 : -1; - // int32_t err = dx - dy; -// - // while (1) { - // // TODO(kard): "preprocess" line for this check to not be necessary - // // actually idk what is faster and how much line needs to be outside, check - // if (x0 >= 0 && x0 < (int32_t)c.width && y0 >= 0 && y0 < (int32_t)c.height) - // c.pixels[(y0 * c.stride) + x0] = color; -// - // if (x0 == x1 && y0 == y1) break; -// - // int32_t e2 = 2 * err; - // if (e2 > -dy) { err -= dy; x0 += sx; } - // if (e2 < dx) { err += dx; y0 += sy; } - // } - } #endif // SPONGE_IMPLEMENTATION -- cgit v1.3.1