Document/ignore GPU features without universal support

include/SDL3/SDL_gpu.h

@@ -1495,6 +1495,9 @@ typedef struct SDL_GPUIndirectDispatchCommand
 /**
  * A structure specifying the parameters of a sampler.
  *
+ * Note that mip_lod_bias is a no-op for the Metal driver.
+ * For Metal, LOD bias must be applied via shader instead.
+ *
  * \since This function is available since SDL 3.2.0.
  *
  * \sa SDL_CreateGPUSampler
@@ -1547,7 +1550,7 @@ typedef struct SDL_GPUVertexBufferDescription
     Uint32 slot;                        /**< The binding slot of the vertex buffer. */
     Uint32 pitch;                       /**< The byte pitch between consecutive elements of the vertex buffer. */
     SDL_GPUVertexInputRate input_rate;  /**< Whether attribute addressing is a function of the vertex index or instance index. */
-    Uint32 instance_step_rate;          /**< The number of instances to draw using the same per-instance data before advancing in the instance buffer by one element. Ignored unless input_rate is SDL_GPU_VERTEXINPUTRATE_INSTANCE */
+    Uint32 instance_step_rate;          /**< Ignored, reserved for future use. */
 } SDL_GPUVertexBufferDescription;
 
 /**
@@ -1717,10 +1720,13 @@ typedef struct SDL_GPUTransferBufferCreateInfo
  * A structure specifying the parameters of the graphics pipeline rasterizer
  * state.
  *
- * NOTE: Some backend APIs (D3D11/12) will enable depth clamping even if
- * enable_depth_clip is true. If you rely on this clamp+clip behavior,
- * consider enabling depth clip and then manually clamping depth in your
- * fragment shaders on Metal and Vulkan.
+ * Note that SDL_GPU_FILLMODE_LINE is not supported on many Android devices.
+ * For those devices, the fill mode will automatically fall back to FILL.
+ *
+ * Also note that the D3D12 driver will enable depth clamping even if
+ * enable_depth_clip is true. If you need this clamp+clip behavior, consider
+ * enabling depth clip and then manually clamping depth in your fragment
+ * shaders on Metal and Vulkan.
  *
  * \since This struct is available since SDL 3.2.0.
  *
@@ -1751,8 +1757,8 @@ typedef struct SDL_GPURasterizerState
 typedef struct SDL_GPUMultisampleState
 {
     SDL_GPUSampleCount sample_count;  /**< The number of samples to be used in rasterization. */
-    Uint32 sample_mask;               /**< Determines which samples get updated in the render targets. Treated as 0xFFFFFFFF if enable_mask is false. */
-    bool enable_mask;             /**< Enables sample masking. */
+    Uint32 sample_mask;               /**< Ignored, reserved for future use. */
+    bool enable_mask;             /**< Ignored, reserved for future use. */
     Uint8 padding1;
     Uint8 padding2;
     Uint8 padding3;

src/gpu/d3d12/SDL_gpu_d3d12.c

@@ -2928,7 +2928,7 @@ static bool D3D12_INTERNAL_ConvertVertexInputState(SDL_GPUVertexInputState verte
         desc[i].AlignedByteOffset = attribute.offset;
         desc[i].InputSlotClass = SDLToD3D12_InputRate[vertexInputState.vertex_buffer_descriptions[attribute.buffer_slot].input_rate];
         desc[i].InstanceDataStepRate = (vertexInputState.vertex_buffer_descriptions[attribute.buffer_slot].input_rate == SDL_GPU_VERTEXINPUTRATE_INSTANCE)
-            ? vertexInputState.vertex_buffer_descriptions[attribute.buffer_slot].instance_step_rate
+            ? 1
             : 0;
     }
 
@@ -3010,11 +3010,7 @@ static SDL_GPUGraphicsPipeline *D3D12_CreateGraphicsPipeline(
         return NULL;
     }
 
-    Uint32 sampleMask = createinfo->multisample_state.enable_mask ?
-        createinfo->multisample_state.sample_mask :
-        0xFFFFFFFF;
-
-    psoDesc.SampleMask = sampleMask;
+    psoDesc.SampleMask = 0xFFFFFFFF;
     psoDesc.SampleDesc.Count = SDLToD3D12_SampleCount[createinfo->multisample_state.sample_count];
     psoDesc.SampleDesc.Quality = (createinfo->multisample_state.sample_count > SDL_GPU_SAMPLECOUNT_1) ? D3D12_STANDARD_MULTISAMPLE_PATTERN : 0;
 

src/gpu/metal/SDL_gpu_metal.m

@@ -478,8 +478,6 @@ typedef struct MetalGraphicsPipeline
 {
     id<MTLRenderPipelineState> handle;
 
-    Uint32 sample_mask;
-
     SDL_GPURasterizerState rasterizerState;
     SDL_GPUPrimitiveType primitiveType;
 
@@ -1181,9 +1179,7 @@ static SDL_GPUGraphicsPipeline *METAL_CreateGraphicsPipeline(
             for (Uint32 i = 0; i < createinfo->vertex_input_state.num_vertex_buffers; i += 1) {
                 binding = METAL_FIRST_VERTEX_BUFFER_SLOT + createinfo->vertex_input_state.vertex_buffer_descriptions[i].slot;
                 vertexDescriptor.layouts[binding].stepFunction = SDLToMetal_StepFunction[createinfo->vertex_input_state.vertex_buffer_descriptions[i].input_rate];
-                vertexDescriptor.layouts[binding].stepRate = (createinfo->vertex_input_state.vertex_buffer_descriptions[i].input_rate == SDL_GPU_VERTEXINPUTRATE_INSTANCE)
-                    ? createinfo->vertex_input_state.vertex_buffer_descriptions[i].instance_step_rate
-                    : 1;
+                vertexDescriptor.layouts[binding].stepRate = 1;
                 vertexDescriptor.layouts[binding].stride = createinfo->vertex_input_state.vertex_buffer_descriptions[i].pitch;
             }
 
@@ -1202,13 +1198,8 @@ static SDL_GPUGraphicsPipeline *METAL_CreateGraphicsPipeline(
             SET_ERROR_AND_RETURN("Creating render pipeline failed: %s", [[error description] UTF8String], NULL);
         }
 
-        Uint32 sampleMask = createinfo->multisample_state.enable_mask ?
-            createinfo->multisample_state.sample_mask :
-            0xFFFFFFFF;
-
         result = SDL_calloc(1, sizeof(MetalGraphicsPipeline));
         result->handle = pipelineState;
-        result->sample_mask = sampleMask;
         result->depth_stencil_state = depthStencilState;
         result->rasterizerState = createinfo->rasterizer_state;
         result->primitiveType = createinfo->primitive_type;

src/gpu/vulkan/SDL_gpu_vulkan.c

@@ -56,8 +56,6 @@ typedef struct VulkanExtensions
 
     // Core since 1.2, but requires annoying paperwork to implement
     Uint8 KHR_driver_properties;
-    // EXT, probably not going to be Core
-    Uint8 EXT_vertex_attribute_divisor;
     // Only required for special implementations (i.e. MoltenVK)
     Uint8 KHR_portability_subset;
     // Only required for decoding HDR ASTC textures
@@ -6202,11 +6200,8 @@ static SDL_GPUGraphicsPipeline *VULKAN_CreateGraphicsPipeline(
     VkPipelineShaderStageCreateInfo shaderStageCreateInfos[2];
 
     VkPipelineVertexInputStateCreateInfo vertexInputStateCreateInfo;
-    VkPipelineVertexInputDivisorStateCreateInfoEXT divisorStateCreateInfo;
     VkVertexInputBindingDescription *vertexInputBindingDescriptions = SDL_stack_alloc(VkVertexInputBindingDescription, createinfo->vertex_input_state.num_vertex_buffers);
     VkVertexInputAttributeDescription *vertexInputAttributeDescriptions = SDL_stack_alloc(VkVertexInputAttributeDescription, createinfo->vertex_input_state.num_vertex_attributes);
-    VkVertexInputBindingDivisorDescriptionEXT *divisorDescriptions = SDL_stack_alloc(VkVertexInputBindingDivisorDescriptionEXT, createinfo->vertex_input_state.num_vertex_buffers);
-    Uint32 divisorDescriptionCount = 0;
 
     VkPipelineInputAssemblyStateCreateInfo inputAssemblyStateCreateInfo;
 
@@ -6289,10 +6284,6 @@ static SDL_GPUGraphicsPipeline *VULKAN_CreateGraphicsPipeline(
         vertexInputBindingDescriptions[i].binding = createinfo->vertex_input_state.vertex_buffer_descriptions[i].slot;
         vertexInputBindingDescriptions[i].inputRate = SDLToVK_VertexInputRate[createinfo->vertex_input_state.vertex_buffer_descriptions[i].input_rate];
         vertexInputBindingDescriptions[i].stride = createinfo->vertex_input_state.vertex_buffer_descriptions[i].pitch;
-
-        if (createinfo->vertex_input_state.vertex_buffer_descriptions[i].input_rate == SDL_GPU_VERTEXINPUTRATE_INSTANCE) {
-            divisorDescriptionCount += 1;
-        }
     }
 
     for (i = 0; i < createinfo->vertex_input_state.num_vertex_attributes; i += 1) {
@@ -6310,26 +6301,6 @@ static SDL_GPUGraphicsPipeline *VULKAN_CreateGraphicsPipeline(
     vertexInputStateCreateInfo.vertexAttributeDescriptionCount = createinfo->vertex_input_state.num_vertex_attributes;
     vertexInputStateCreateInfo.pVertexAttributeDescriptions = vertexInputAttributeDescriptions;
 
-    if (divisorDescriptionCount > 0) {
-        divisorDescriptionCount = 0;
-
-        for (i = 0; i < createinfo->vertex_input_state.num_vertex_buffers; i += 1) {
-            if (createinfo->vertex_input_state.vertex_buffer_descriptions[i].input_rate == SDL_GPU_VERTEXINPUTRATE_INSTANCE) {
-                divisorDescriptions[divisorDescriptionCount].binding = createinfo->vertex_input_state.vertex_buffer_descriptions[i].slot;
-                divisorDescriptions[divisorDescriptionCount].divisor = createinfo->vertex_input_state.vertex_buffer_descriptions[i].instance_step_rate;
-
-                divisorDescriptionCount += 1;
-            }
-        }
-
-        divisorStateCreateInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_DIVISOR_STATE_CREATE_INFO_EXT;
-        divisorStateCreateInfo.pNext = NULL;
-        divisorStateCreateInfo.vertexBindingDivisorCount = divisorDescriptionCount;
-        divisorStateCreateInfo.pVertexBindingDivisors = divisorDescriptions;
-
-        vertexInputStateCreateInfo.pNext = &divisorStateCreateInfo;
-    }
-
     // Topology
 
     inputAssemblyStateCreateInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO;
@@ -6376,9 +6347,7 @@ static SDL_GPUGraphicsPipeline *VULKAN_CreateGraphicsPipeline(
 
     // Multisample
 
-    Uint32 sampleMask = createinfo->multisample_state.enable_mask ?
-        createinfo->multisample_state.sample_mask :
-        0xFFFFFFFF;
+    Uint32 sampleMask = 0xFFFFFFFF;
 
     multisampleStateCreateInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO;
     multisampleStateCreateInfo.pNext = NULL;
@@ -6476,7 +6445,6 @@ static SDL_GPUGraphicsPipeline *VULKAN_CreateGraphicsPipeline(
         SDL_stack_free(vertexInputBindingDescriptions);
         SDL_stack_free(vertexInputAttributeDescriptions);
         SDL_stack_free(colorBlendAttachmentStates);
-        SDL_stack_free(divisorDescriptions);
         SDL_free(graphicsPipeline);
         SET_STRING_ERROR_AND_RETURN("Failed to initialize pipeline resource layout!", NULL);
     }
@@ -6515,7 +6483,6 @@ static SDL_GPUGraphicsPipeline *VULKAN_CreateGraphicsPipeline(
     SDL_stack_free(vertexInputBindingDescriptions);
     SDL_stack_free(vertexInputAttributeDescriptions);
     SDL_stack_free(colorBlendAttachmentStates);
-    SDL_stack_free(divisorDescriptions);
 
     renderer->vkDestroyRenderPass(
         renderer->logicalDevice,
@@ -10898,7 +10865,7 @@ static inline Uint8 CheckDeviceExtensions(
         supports->ext = 1;                   \
     }
         CHECK(KHR_swapchain)
-        else CHECK(KHR_maintenance1) else CHECK(KHR_driver_properties) else CHECK(EXT_vertex_attribute_divisor) else CHECK(KHR_portability_subset) else CHECK(EXT_texture_compression_astc_hdr)
+        else CHECK(KHR_maintenance1) else CHECK(KHR_driver_properties) CHECK(KHR_portability_subset) else CHECK(EXT_texture_compression_astc_hdr)
 #undef CHECK
     }
 
@@ -10912,7 +10879,6 @@ static inline Uint32 GetDeviceExtensionCount(VulkanExtensions *supports)
         supports->KHR_swapchain +
         supports->KHR_maintenance1 +
         supports->KHR_driver_properties +
-        supports->EXT_vertex_attribute_divisor +
         supports->KHR_portability_subset +
         supports->EXT_texture_compression_astc_hdr);
 }
@@ -10929,7 +10895,6 @@ static inline void CreateDeviceExtensionArray(
     CHECK(KHR_swapchain)
     CHECK(KHR_maintenance1)
     CHECK(KHR_driver_properties)
-    CHECK(EXT_vertex_attribute_divisor)
     CHECK(KHR_portability_subset)
     CHECK(EXT_texture_compression_astc_hdr)
 #undef CHECK