[pull] master from beyond-all-reason:master

doc/pr-changelogs/3374.md

@@ -0,0 +1,5 @@
+### Features
+ * glTF models now load the `COLOR_0` vertex attribute. Model shaders can read it as `layout (location = 15) in vec4 color`, and Lua as the `color` attribute of `VBO:ModelsVBO()`. Models without it (including all S3O, 3DO and assimp models) read opaque white. `Engine.FeatureSupport.modelVertexColor` is `true` on engines that have it.
+
+### Caveats
+ * one element of `VBO:ModelsVBO()` is now 80 bytes instead of 76; Lua code that hardcoded the old stride needs updating.

rts/Lua/LuaConstEngine.cpp

@@ -31,6 +31,7 @@
  * @field reliableLuaMapShaders boolean Whether forward-only Lua map shaders activate without a deferred draw and Spring.SetMapShader program swaps refresh cached uniform locations
  * @field nanoParticleUpdateCallin boolean Whether LuaUI receives batched `NanoParticleUpdate` lifecycle events
  * @field nanoParticlesGL4 boolean Whether the engine has the standalone shader-based nano particle effect (the `NanoParticles*` springsettings)
+ * @field modelVertexColor boolean Whether glTF `COLOR_0` is loaded into the models VBO (`color`, attribute 15; opaque white when absent)
  */
 
 /***
@@ -89,6 +90,7 @@ bool LuaConstEngine::PushEntries(lua_State* L)
 		LuaPushNamedBool(L, "reliableLuaMapShaders", true);
 		LuaPushNamedBool(L, "nanoParticleUpdateCallin", true);
 		LuaPushNamedBool(L, "nanoParticlesGL4", true);
+		LuaPushNamedBool(L, "modelVertexColor", true);
 	lua_rawset(L, -3);
 
 	lua_pushliteral(L, "textColorCodes");

rts/Lua/LuaVBOImpl.cpp

@@ -814,6 +814,7 @@ void LuaVBOImpl::UpdateModelsVBOElementCount()
 	//   support an arbitrary number of channels, would be easy but overkill (for now)
 	float2 texCoords[NUM_MODEL_UVCHANNS];
 	uvec3 in uvec3 bonesInfo;
+	u8vec4 color;
 */
 size_t LuaVBOImpl::ModelsVBOImpl()
 {
@@ -884,7 +885,18 @@ size_t LuaVBOImpl::ModelsVBOImpl()
 			3 * sizeof(uint32_t) //strideSizeInBytes
 		};
 
-		this->attributesCount = 6;
+		// uint8_t color[4]
+		this->bufferAttribDefs[15] = {
+			GL_UNSIGNED_BYTE, //type
+			4, //size
+			GL_TRUE, //normalized
+			"color", //name
+			offsetof(SVertexData, color), //pointer
+			sizeof(uint8_t), //typeSizeInBytes
+			4 * sizeof(uint8_t) //strideSizeInBytes
+		};
+
+		this->attributesCount = 7;
 		this->elemSizeInBytes = sizeof(SVertexData);
 		this->bufferSizeInBytes = vbo->GetSize();
 		this->elementsCount = S3DModelVAO::GetInstance().GetVertElemCount();

rts/Rendering/Models/3DModelVAO.cpp

@@ -31,6 +31,11 @@ void S3DModelVAO::EnableAttribs(bool inst) const
 		glVertexAttribPointer (3, 3, GL_FLOAT       , false, sizeof(SVertexData), (const void*)offsetof(SVertexData, tTangent    ));
 		glVertexAttribPointer (4, 4, GL_FLOAT       , false, sizeof(SVertexData), (const void*)offsetof(SVertexData, texCoords[0]));
 		glVertexAttribIPointer(5, 3, GL_UNSIGNED_INT,        sizeof(SVertexData), (const void*)offsetof(SVertexData, boneIDsLow  ));
+
+		// last guaranteed slot, Lua VAOs on this buffer put their instance attribs from 6 up
+		glEnableVertexAttribArray(15);
+		glVertexAttribDivisor(15, 0);
+		glVertexAttribPointer (15, 4, GL_UNSIGNED_BYTE, true , sizeof(SVertexData), (const void*)offsetof(SVertexData, color       ));
 	}
 	else {
 		for (int i = 6; i <= 6; ++i) {
@@ -50,6 +55,8 @@ void S3DModelVAO::DisableAttribs() const
 		glDisableVertexAttribArray(i);
 		glVertexAttribDivisor(i, 0);
 	}
+
+	glDisableVertexAttribArray(15);
 }
 
 S3DModelVAO::S3DModelVAO()

rts/Rendering/Models/GLTFParser.cpp

@@ -131,6 +131,18 @@ namespace Impl {
 						});
 						seenTangents = true;
 					} break;
+					case hashString("COLOR_0"): {
+						const auto ToByte = [](float v) { return static_cast<uint8_t>(std::clamp(v, 0.0f, 1.0f) * 255.0f + 0.5f); };
+						if (accessor.type == fastgltf::AccessorType::Vec3) {
+							fastgltf::iterateAccessorWithIndex<fastgltf::math::fvec3>(asset, accessor, [&](const auto& val, std::size_t idx) {
+								verts[prevVertSize + idx].color = { ToByte(val.x()), ToByte(val.y()), ToByte(val.z()), 255 };
+							});
+						} else if (accessor.type == fastgltf::AccessorType::Vec4) {
+							fastgltf::iterateAccessorWithIndex<fastgltf::math::fvec4>(asset, accessor, [&](const auto& val, std::size_t idx) {
+								verts[prevVertSize + idx].color = { ToByte(val.x()), ToByte(val.y()), ToByte(val.z()), ToByte(val.w()) };
+							});
+						}
+					} break;
 					case hashString("JOINTS_0"): {
 						assert(skinPtr);
 						fastgltf::iterateAccessorWithIndex<fastgltf::math::uvec4>(asset, accessor, [&](const auto& val, std::size_t idx) {

rts/Rendering/Models/VertexData.cpp

@@ -1,6 +1,6 @@
 #include "VertexData.hpp"
 
-static_assert(sizeof(SVertexData) == (3 + 3 + 3 + 3 + 4 + 2 + 1) * 4);
+static_assert(sizeof(SVertexData) == (3 + 3 + 3 + 3 + 4 + 2 + 1 + 1) * 4);
 
 void SVertexData::TransformBy(const Transform& transform)
 {

rts/Rendering/Models/VertexData.hpp

@@ -23,6 +23,7 @@ struct SVertexData {
 		boneIDsLow  = DEFAULT_BONEIDS_LOW;
 		boneWeights = DEFAULT_BONEWEIGHTS;
 		boneIDsHigh = DEFAULT_BONEIDS_HIGH;
+		color       = DEFAULT_COLOR;
 	}
 	SVertexData(
 		const float3& p,
@@ -42,12 +43,14 @@ struct SVertexData {
 		boneIDsLow  = DEFAULT_BONEIDS_LOW;
 		boneWeights = DEFAULT_BONEWEIGHTS;
 		boneIDsHigh = DEFAULT_BONEIDS_HIGH;
+		color       = DEFAULT_COLOR;
 	}
 
 	static constexpr size_t NUM_MODEL_UVCHANNS = 2;
 	static constexpr std::array<uint8_t, 4> DEFAULT_BONEIDS_HIGH = { 255, 255, 255, 255 };
 	static constexpr std::array<uint8_t, 4> DEFAULT_BONEIDS_LOW = { 255, 255, 255, 255 };
 	static constexpr std::array<uint8_t, 4> DEFAULT_BONEWEIGHTS = { 255, 0  ,   0,   0 };
+	static constexpr std::array<uint8_t, 4> DEFAULT_COLOR       = { 255, 255, 255, 255 };
 	static constexpr uint16_t INVALID_BONEID = 0xFFFF;
 	static constexpr size_t MAX_BONES_PER_VERTEX = 4;
 
@@ -61,6 +64,8 @@ struct SVertexData {
 	std::array<uint8_t, MAX_BONES_PER_VERTEX> boneWeights;
 	std::array<uint8_t, MAX_BONES_PER_VERTEX> boneIDsHigh;
 
+	std::array<uint8_t, 4> color;
+
 	template <Concepts::HasSizeAndData C>
 	void SetBones(const C& bi) {
 		static_assert(std::is_same_v<typename C::value_type, std::pair<uint16_t, float>>);