diff options
Diffstat (limited to 'Userland/Libraries/LibGL/SoftwareRasterizer.cpp')
| -rw-r--r-- | Userland/Libraries/LibGL/SoftwareRasterizer.cpp | 96 |
1 files changed, 61 insertions, 35 deletions
diff --git a/Userland/Libraries/LibGL/SoftwareRasterizer.cpp b/Userland/Libraries/LibGL/SoftwareRasterizer.cpp index 1867b33188..25cd5df6dd 100644 --- a/Userland/Libraries/LibGL/SoftwareRasterizer.cpp +++ b/Userland/Libraries/LibGL/SoftwareRasterizer.cpp @@ -94,6 +94,9 @@ static void rasterize_triangle(const RasterizerOptions& options, Gfx::Bitmap& re const int by1 = min(render_target.height(), max(max(v0.y(), v1.y()), v2.y()) + RASTERIZER_BLOCK_SIZE - 1) / RASTERIZER_BLOCK_SIZE; // clang-format on + static_assert(RASTERIZER_BLOCK_SIZE < sizeof(int) * 8, "RASTERIZER_BLOCK_SIZE must be smaller than the pixel_mask's width in bits"); + int pixel_mask[RASTERIZER_BLOCK_SIZE]; + // Iterate over all blocks within the bounds of the triangle for (int by = by0; by < by1; by++) { for (int bx = bx0; bx < bx1; bx++) { @@ -126,53 +129,76 @@ static void rasterize_triangle(const RasterizerOptions& options, Gfx::Bitmap& re int x0 = bx * RASTERIZER_BLOCK_SIZE; int y0 = by * RASTERIZER_BLOCK_SIZE; - int x1 = x0 + RASTERIZER_BLOCK_SIZE; - int y1 = y0 + RASTERIZER_BLOCK_SIZE; + // Generate the coverage mask if (test_point(b0) && test_point(b1) && test_point(b2) && test_point(b3)) { - // The block is fully contained within the triangle - // Fill the block without further coverage tests + // The block is fully contained within the triangle. Fill the mask with all 1s + for (int y = 0; y < RASTERIZER_BLOCK_SIZE; y++) { + pixel_mask[y] = -1; + } + } else { + // The block overlaps at least one triangle edge. + // We need to test coverage of every pixel within the block. auto coords = b0; - for (int y = y0; y < y1; y++, coords += step_y) { - auto* pixel = &render_target.scanline(y)[x0]; - auto* depth = &depth_buffer.scanline(y)[x0]; - for (int x = x0; x < x1; x++, coords += dbdx, pixel++, depth++) { - auto barycentric = FloatVector3(coords.x(), coords.y(), coords.z()) * one_over_area; - if (options.enable_depth_test) { - float z = interpolate(triangle.vertices[0].z, triangle.vertices[1].z, triangle.vertices[2].z, barycentric); - if (z < *depth) { - *pixel = to_rgba32(pixel_shader(barycentric, triangle)); - *depth = z; - } - } else { - *pixel = to_rgba32(pixel_shader(barycentric, triangle)); - } + for (int y = 0; y < RASTERIZER_BLOCK_SIZE; y++, coords += step_y) { + pixel_mask[y] = 0; + + for (int x = 0; x < RASTERIZER_BLOCK_SIZE; x++, coords += dbdx) { + if (test_point(coords)) + pixel_mask[y] |= 1 << x; } } - } else { - // The block overlaps at least one triangle edge - // We need to test coverage of every pixel within the block + } + + // AND the depth mask onto the coverage mask + if (options.enable_depth_test) { + int z_pass_count = 0; auto coords = b0; - for (int y = y0; y < y1; y++, coords += step_y) { - auto* pixel = &render_target.scanline(y)[x0]; - auto* depth = &depth_buffer.scanline(y)[x0]; - for (int x = x0; x < x1; x++, coords += dbdx, pixel++, depth++) { - - if (!test_point(coords)) + + for (int y = 0; y < RASTERIZER_BLOCK_SIZE; y++, coords += step_y) { + if (pixel_mask[y] == 0) { + coords += dbdx * RASTERIZER_BLOCK_SIZE; + continue; + } + + auto* depth = &depth_buffer.scanline(y0 + y)[x0]; + for (int x = 0; x < RASTERIZER_BLOCK_SIZE; x++, coords += dbdx, depth++) { + if (~pixel_mask[y] & (1 << x)) continue; auto barycentric = FloatVector3(coords.x(), coords.y(), coords.z()) * one_over_area; - if (options.enable_depth_test) { - float z = interpolate(triangle.vertices[0].z, triangle.vertices[1].z, triangle.vertices[2].z, barycentric); - if (z < *depth) { - *pixel = to_rgba32(pixel_shader(barycentric, triangle)); - *depth = z; - } - } else { - *pixel = to_rgba32(pixel_shader(barycentric, triangle)); + float z = interpolate(triangle.vertices[0].z, triangle.vertices[1].z, triangle.vertices[2].z, barycentric); + if (z >= *depth) { + pixel_mask[y] ^= 1 << x; + continue; } + + *depth = z; + z_pass_count++; } } + + // Nice, no pixels passed the depth test -> block rejected by early z + if (z_pass_count == 0) + continue; + } + + // Draw the pixels according to the previously generated mask + auto coords = b0; + for (int y = 0; y < RASTERIZER_BLOCK_SIZE; y++, coords += step_y) { + if (pixel_mask[y] == 0) { + coords += dbdx * RASTERIZER_BLOCK_SIZE; + continue; + } + + auto* pixel = &render_target.scanline(y0 + y)[x0]; + for (int x = 0; x < RASTERIZER_BLOCK_SIZE; x++, coords += dbdx, pixel++) { + if (~pixel_mask[y] & (1 << x)) + continue; + + auto barycentric = FloatVector3(coords.x(), coords.y(), coords.z()) * one_over_area; + *pixel = to_rgba32(pixel_shader(barycentric, triangle)); + } } } } |