add 'shaderatomics' field to love.graphics.getTextureFormats' usage table arg.

Currently only r32i and r32ui are supported (on capable systems).

src/modules/graphics/Texture.h

@@ -60,12 +60,13 @@ enum TextureType
 
 enum PixelFormatUsage
 {
-	PIXELFORMATUSAGE_SAMPLE,       // Any sampling in shaders.
-	PIXELFORMATUSAGE_LINEAR,       // Linear filtering.
-	PIXELFORMATUSAGE_RENDERTARGET, // Usable as a render target.
-	PIXELFORMATUSAGE_BLEND,        // Blend support when used as a render target.
-	PIXELFORMATUSAGE_MSAA,         // MSAA support when used as a render target.
-	PIXELFORMATUSAGE_COMPUTEWRITE, // Writable in compute shaders via imageStore.
+	PIXELFORMATUSAGE_SAMPLE,        // Any sampling in shaders.
+	PIXELFORMATUSAGE_LINEAR,        // Linear filtering.
+	PIXELFORMATUSAGE_RENDERTARGET,  // Usable as a render target.
+	PIXELFORMATUSAGE_BLEND,         // Blend support when used as a render target.
+	PIXELFORMATUSAGE_MSAA,          // MSAA support when used as a render target.
+	PIXELFORMATUSAGE_COMPUTEWRITE,  // Writable in compute shaders via imageStore.
+	PIXELFORMATUSAGE_SHADERATOMICS, // Supports atomic load/store in compute shaders.
 	PIXELFORMATUSAGE_MAX_ENUM
 };
 
@@ -78,6 +79,7 @@ enum PixelFormatUsageFlags
 	PIXELFORMATUSAGEFLAGS_BLEND = (1 << PIXELFORMATUSAGE_BLEND),
 	PIXELFORMATUSAGEFLAGS_MSAA = (1 << PIXELFORMATUSAGE_MSAA),
 	PIXELFORMATUSAGEFLAGS_COMPUTEWRITE = (1 << PIXELFORMATUSAGE_COMPUTEWRITE),
+	PIXELFORMATUSAGEFLAGS_SHADERATOMICS = (1 << PIXELFORMATUSAGE_SHADERATOMICS),
 };
 
 struct SamplerState

src/modules/graphics/opengl/OpenGL.cpp

@@ -1990,6 +1990,11 @@ uint32 OpenGL::getPixelFormatUsageFlags(PixelFormat pixelformat)
 	case PIXELFORMAT_RGBA32_UINT:
 	case PIXELFORMAT_RGB10A2_UINT:
 		flags |= PIXELFORMATUSAGEFLAGS_SAMPLE | PIXELFORMATUSAGEFLAGS_RENDERTARGET;
+		if (pixelformat == PIXELFORMAT_R32_INT || pixelformat == PIXELFORMAT_R32_UINT)
+		{
+			if (GLAD_VERSION_4_3 || GLAD_ES_VERSION_3_2)
+				flags |= PIXELFORMATUSAGEFLAGS_SHADERATOMICS;
+		}
 		if (GLAD_VERSION_4_3)
 			flags |= computewrite;
 		if (GLAD_ES_VERSION_3_1)

src/modules/graphics/vulkan/Graphics.cpp

@@ -1237,6 +1237,16 @@ bool Graphics::isPixelFormatSupported(PixelFormat format, uint32 usage)
 			return false;
 	}
 
+	if (usage & PIXELFORMATUSAGEFLAGS_SHADERATOMICS)
+	{
+		if (!(featureFlags & VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT))
+			return false;
+
+		// TODO: supporting float formats when available may need GLSL extensions.
+		if (format != PIXELFORMAT_R32_INT && format != PIXELFORMAT_R32_UINT)
+			return false;
+	}
+
 	if (usage & PIXELFORMATUSAGEFLAGS_MSAA)
 	{
 		VkImageFormatProperties properties;

src/modules/graphics/wrap_Graphics.cpp

@@ -3007,6 +3007,7 @@ int w_getTextureFormats(lua_State *L)
 
 	bool rt = luax_checkboolflag(L, 1, Texture::getConstant(Texture::SETTING_RENDER_TARGET));
 	bool computewrite = luax_boolflag(L, 1, Texture::getConstant(Texture::SETTING_COMPUTE_WRITE), false);
+	bool shaderatomics = luax_boolflag(L, 1, "shaderatomics", false);
 
 	OptionalBool readable;
 	lua_getfield(L, 1, Texture::getConstant(Texture::SETTING_READABLE));
@@ -3034,6 +3035,8 @@ int w_getTextureFormats(lua_State *L)
 			usage |= PIXELFORMATUSAGEFLAGS_SAMPLE;
 		if (computewrite)
 			usage |= PIXELFORMATUSAGEFLAGS_COMPUTEWRITE;
+		if (shaderatomics)
+			usage |= PIXELFORMATUSAGEFLAGS_SHADERATOMICS;
 
 		luax_pushboolean(L, instance()->isPixelFormatSupported(format, (PixelFormatUsageFlags) usage));
 		lua_setfield(L, -2, name);