From 3343cb21473ea454261bc4187393aaec9cc3f28f Mon Sep 17 00:00:00 2001
From: Eri the Switch <[EMAIL REDACTED]>
Date: Sun, 6 Apr 2025 19:22:59 +0300
Subject: [PATCH] gpu: rework alpha-to-coverage validation
---
src/gpu/SDL_gpu.c | 20 +++++++----
src/gpu/SDL_sysgpu.h | 83 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 97 insertions(+), 6 deletions(-)
diff --git a/src/gpu/SDL_gpu.c b/src/gpu/SDL_gpu.c
index 44979a59de705..7532c3a64de7a 100644
--- a/src/gpu/SDL_gpu.c
+++ b/src/gpu/SDL_gpu.c
@@ -827,12 +827,6 @@ SDL_GPUGraphicsPipeline *SDL_CreateGPUGraphicsPipeline(
SDL_assert_release(!"Format is not supported for color targets on this device!");
return NULL;
}
- if (graphicsPipelineCreateInfo->multisample_state.enable_alpha_to_coverage &&
- (IsIntegerFormat(graphicsPipelineCreateInfo->target_info.color_target_descriptions[i].format)
- || IsCompressedFormat(graphicsPipelineCreateInfo->target_info.color_target_descriptions[i].format))) {
- SDL_assert_release(!"Format is not compatible with alpha-to-coverage!");
- return NULL;
- }
if (graphicsPipelineCreateInfo->target_info.color_target_descriptions[i].blend_state.enable_blend) {
const SDL_GPUColorTargetBlendState *blend_state = &graphicsPipelineCreateInfo->target_info.color_target_descriptions[i].blend_state;
CHECK_BLENDFACTOR_ENUM_INVALID(blend_state->src_color_blendfactor, NULL)
@@ -841,6 +835,8 @@ SDL_GPUGraphicsPipeline *SDL_CreateGPUGraphicsPipeline(
CHECK_BLENDFACTOR_ENUM_INVALID(blend_state->src_alpha_blendfactor, NULL)
CHECK_BLENDFACTOR_ENUM_INVALID(blend_state->dst_alpha_blendfactor, NULL)
CHECK_BLENDOP_ENUM_INVALID(blend_state->alpha_blend_op, NULL)
+
+ // TODO: validate that format support blending?
}
}
if (graphicsPipelineCreateInfo->target_info.has_depth_stencil_target) {
@@ -854,6 +850,18 @@ SDL_GPUGraphicsPipeline *SDL_CreateGPUGraphicsPipeline(
return NULL;
}
}
+ if (graphicsPipelineCreateInfo->multisample_state.enable_alpha_to_coverage) {
+ if (graphicsPipelineCreateInfo->target_info.num_color_targets < 1) {
+ SDL_assert_release(!"Alpha-to-coverage enabled but no color targets present!");
+ return NULL;
+ }
+ if (!FormatHasAlpha(graphicsPipelineCreateInfo->target_info.color_target_descriptions[0].format)) {
+ SDL_assert_release(!"Format is not compatible with alpha-to-coverage!");
+ return NULL;
+ }
+
+ // TODO: validate that format supports belnding? This is only required on Metal.
+ }
if (graphicsPipelineCreateInfo->vertex_input_state.num_vertex_buffers > 0 && graphicsPipelineCreateInfo->vertex_input_state.vertex_buffer_descriptions == NULL) {
SDL_assert_release(!"Vertex buffer descriptions array pointer cannot be NULL!");
return NULL;
diff --git a/src/gpu/SDL_sysgpu.h b/src/gpu/SDL_sysgpu.h
index 9a51daebfad43..ddcfe57e77ad3 100644
--- a/src/gpu/SDL_sysgpu.h
+++ b/src/gpu/SDL_sysgpu.h
@@ -438,6 +438,89 @@ static inline bool IsCompressedFormat(
}
}
+static inline bool FormatHasAlpha(
+ SDL_GPUTextureFormat format)
+{
+ switch (format) {
+ case SDL_GPU_TEXTUREFORMAT_ASTC_12x10_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_12x12_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_12x10_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_12x12_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_12x10_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_12x12_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x5_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x6_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x8_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x10_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x5_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x6_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x8_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x10_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x5_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x6_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x8_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_10x10_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x5_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x6_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x8_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x5_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x6_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x8_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x5_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x6_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_8x8_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_6x5_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_6x6_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_6x5_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_6x6_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_6x5_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_6x6_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_5x4_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_5x5_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_5x4_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_5x5_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_5x4_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_5x5_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_4x4_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_4x4_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_ASTC_4x4_FLOAT:
+ // ASTC textures may or may not have alpha; return true as this is mainly intended for validation
+ return true;
+
+ case SDL_GPU_TEXTUREFORMAT_BC1_RGBA_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_BC2_RGBA_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_BC3_RGBA_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_BC7_RGBA_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_BC1_RGBA_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_BC2_RGBA_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_BC3_RGBA_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_BC7_RGBA_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_B8G8R8A8_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_B5G5R5A1_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_B4G4R4A4_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_R10G10B10A2_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_R16G16B16A16_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_A8_UNORM:
+ case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_SNORM:
+ case SDL_GPU_TEXTUREFORMAT_R16G16B16A16_SNORM:
+ case SDL_GPU_TEXTUREFORMAT_R16G16B16A16_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_R32G32B32A32_FLOAT:
+ case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UINT:
+ case SDL_GPU_TEXTUREFORMAT_R16G16B16A16_UINT:
+ case SDL_GPU_TEXTUREFORMAT_R32G32B32A32_UINT:
+ case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_INT:
+ case SDL_GPU_TEXTUREFORMAT_R16G16B16A16_INT:
+ case SDL_GPU_TEXTUREFORMAT_R32G32B32A32_INT:
+ case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM_SRGB:
+ case SDL_GPU_TEXTUREFORMAT_B8G8R8A8_UNORM_SRGB:
+ return true;
+
+ default:
+ return false;
+ }
+}
+
static inline Uint32 IndexSize(SDL_GPUIndexElementSize size)
{
return (size == SDL_GPU_INDEXELEMENTSIZE_16BIT) ? 2 : 4;