Implement fog

.github/gles.patch

@@ -21,7 +21,7 @@ index 990e2f80..2e7842ac 100644
 
  void main() {
 diff --git a/src/host_shaders/opengl_fragment_shader.frag b/src/host_shaders/opengl_fragment_shader.frag
-index 9f369e39..b4bb19d3 100644
+index b9f9fe4c..f1cf286f 100644
 --- a/src/host_shaders/opengl_fragment_shader.frag
 +++ b/src/host_shaders/opengl_fragment_shader.frag
 @@ -1,4 +1,5 @@
@@ -31,8 +31,8 @@ index 9f369e39..b4bb19d3 100644
 
  in vec4 v_quaternion;
  in vec4 v_colour;
-@@ -164,11 +165,17 @@ float lutLookup(uint lut, int index) {
- 	return texelFetch(u_tex_lighting_lut, ivec2(index, int(lut)), 0).r;
+@@ -166,11 +167,17 @@ float lutLookup(uint lut, int index) {
+ 	return texelFetch(u_tex_luts, ivec2(index, int(lut)), 0).r;
  }
 
 +// some gles versions have bitfieldExtractCompat and complain if you redefine it, some don't and compile error, using this instead
@@ -50,7 +50,7 @@ index 9f369e39..b4bb19d3 100644
  }
 
  // Convert an arbitrary-width floating point literal to an f32
-@@ -208,16 +215,16 @@ float lightLutLookup(uint environment_id, uint lut_id, uint light_id, vec3 light
+@@ -210,16 +217,16 @@ float lightLutLookup(uint environment_id, uint lut_id, uint light_id, vec3 light
 
  	bool current_sampler_enabled = isSamplerEnabled(environment_id, lut_id); // 7 luts per environment
 
@@ -70,7 +70,7 @@ index 9f369e39..b4bb19d3 100644
  	switch (input_id) {
  		case 0u: {
  			delta = dot(normal, normalize(half_vector));
-@@ -239,11 +246,11 @@ float lightLutLookup(uint environment_id, uint lut_id, uint light_id, vec3 light
+@@ -241,11 +248,11 @@ float lightLutLookup(uint environment_id, uint lut_id, uint light_id, vec3 light
  			int GPUREG_LIGHTi_SPOTDIR_LOW = int(readPicaReg(0x0146u + (light_id << 4u)));
  			int GPUREG_LIGHTi_SPOTDIR_HIGH = int(readPicaReg(0x0147u + (light_id << 4u)));
 
@@ -86,7 +86,7 @@ index 9f369e39..b4bb19d3 100644
 
  			if ((se_x & 0x1000) == 0x1000) se_x |= 0xffffe000;
  			if ((se_y & 0x1000) == 0x1000) se_y |= 0xffffe000;
-@@ -270,9 +277,9 @@ float lightLutLookup(uint environment_id, uint lut_id, uint light_id, vec3 light
+@@ -272,9 +279,9 @@ float lightLutLookup(uint environment_id, uint lut_id, uint light_id, vec3 light
  	}
 
  	// 0 = enabled
@@ -98,7 +98,7 @@ index 9f369e39..b4bb19d3 100644
  			delta = max(delta, 0.0);
  		} else {
  			delta = abs(delta);
-@@ -296,7 +303,7 @@ vec3 rotateVec3ByQuaternion(vec3 v, vec4 q) {
+@@ -298,7 +305,7 @@ vec3 rotateVec3ByQuaternion(vec3 v, vec4 q) {
  // Implements the following algorthm: https://mathb.in/26766
  void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
  	uint GPUREG_LIGHTING_ENABLE = readPicaReg(0x008Fu);
@@ -107,7 +107,7 @@ index 9f369e39..b4bb19d3 100644
  		primary_color = secondary_color = vec4(0.0);
  		return;
  	}
-@@ -313,7 +320,7 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
+@@ -315,7 +322,7 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
  	GPUREG_LIGHTING_LUTINPUT_ABS = readPicaReg(0x01D0u);
  	GPUREG_LIGHTING_LUTINPUT_SELECT = readPicaReg(0x01D1u);
 
@@ -116,7 +116,7 @@ index 9f369e39..b4bb19d3 100644
 
  	// Bump mode is ignored for now because it breaks some games ie. Toad Treasure Tracker
  	switch (bump_mode) {
-@@ -326,15 +333,15 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
+@@ -328,15 +335,15 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
  	vec4 diffuse_sum = vec4(0.0, 0.0, 0.0, 1.0);
  	vec4 specular_sum = vec4(0.0, 0.0, 0.0, 1.0);
 
@@ -135,7 +135,7 @@ index 9f369e39..b4bb19d3 100644
 
  		uint GPUREG_LIGHTi_SPECULAR0 = readPicaReg(0x0140u + (light_id << 4u));
  		uint GPUREG_LIGHTi_SPECULAR1 = readPicaReg(0x0141u + (light_id << 4u));
-@@ -346,12 +353,12 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
+@@ -348,12 +355,12 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
 
  		float light_distance;
  		vec3 light_position = vec3(
@@ -151,7 +151,7 @@ index 9f369e39..b4bb19d3 100644
  			light_vector = light_position + v_view;
  		}
 
-@@ -367,23 +374,23 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
+@@ -369,23 +376,23 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
  		float NdotL = dot(normal, light_vector);  // N dot Li
 
  		// Two sided diffuse
@@ -181,7 +181,7 @@ index 9f369e39..b4bb19d3 100644
 
  			float distance_attenuation_bias = decodeFP(GPUREG_LIGHTi_ATTENUATION_BIAS, 7u, 12u);
  			float distance_attenuation_scale = decodeFP(GPUREG_LIGHTi_ATTENUATION_SCALE, 7u, 12u);
-@@ -428,8 +435,8 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
+@@ -430,8 +437,8 @@ void calcLighting(out vec4 primary_color, out vec4 secondary_color) {
  		specular_sum.rgb += light_factor * clamp_factor * (specular0 + specular1);
  	}
 

docs/3ds/lighting.md

@@ -56,7 +56,7 @@ lut_id is one of these values
 6 	RR 
 
 lut_index on the other hand represents the actual index of the LUT in the texture
-u_tex_lighting_lut has 24 LUTs and they are used like so:
+u_tex_luts has 24 LUTs for lighting and they are used like so:
 0 		D0
 1 		D1
 2 		is missing because SP uses LUTs 8-15

include/PICA/gpu.hpp

@@ -92,6 +92,9 @@ class GPU {
 	// Set to false by the renderer when the lighting_lut is uploaded ot the GPU
 	bool lightingLUTDirty = false;
 
+	std::array<uint32_t, 128> fogLUT;
+	bool fogLUTDirty = false;
+
 	GPU(Memory& mem, EmulatorConfig& config);
 	void display() { renderer->display(); }
 	void screenshot(const std::string& name) { renderer->screenshot(name); }

include/PICA/pica_frag_config.hpp

@@ -29,6 +29,18 @@ namespace PICA {
 		std::array<u32, 4 * 6> tevConfigs;
 	};
 
+	struct FogConfig {
+		union {
+			u32 raw{};
+
+			BitField<0, 3, FogMode> mode;
+			BitField<3, 1, u32> flipDepth;
+			BitField<8, 8, u32> fogColorR;
+			BitField<16, 8, u32> fogColorG;
+			BitField<24, 8, u32> fogColorB;
+		};
+	};
+
 	struct Light {
 		union {
 			u16 raw;
@@ -189,6 +201,7 @@ namespace PICA {
 	struct FragmentConfig {
 		OutputConfig outConfig;
 		TextureConfig texConfig;
+		FogConfig fogConfig;
 		LightingConfig lighting;
 
 		bool operator==(const FragmentConfig& config) const {
@@ -220,12 +233,18 @@ namespace PICA {
 			setupTevStage(4);
 			setupTevStage(5);
 #undef setupTevStage
+
+			fogConfig.mode = (FogMode)Helpers::getBits<0, 3>(regs[InternalRegs::TexEnvUpdateBuffer]);
+			fogConfig.flipDepth = Helpers::getBit<16>(regs[InternalRegs::TexEnvUpdateBuffer]);
+			fogConfig.fogColorR = Helpers::getBits<0, 8>(regs[InternalRegs::FogColor]);
+			fogConfig.fogColorG = Helpers::getBits<8, 8>(regs[InternalRegs::FogColor]);
+			fogConfig.fogColorB = Helpers::getBits<16, 8>(regs[InternalRegs::FogColor]);
 		}
 	};
 
 	static_assert(
 		std::has_unique_object_representations<OutputConfig>() && std::has_unique_object_representations<TextureConfig>() &&
-		std::has_unique_object_representations<Light>()
+		std::has_unique_object_representations<FogConfig>() && std::has_unique_object_representations<Light>()
 	);
 }  // namespace PICA
 

include/PICA/regs.hpp

@@ -51,6 +51,18 @@ namespace PICA {
 			#undef defineTexEnv
 			// clang-format on
 
+			// Fog registers
+			FogColor = 0xE1,
+			FogLUTIndex = 0xE6,
+			FogLUTData0 = 0xE8,
+			FogLUTData1 = 0xE9,
+			FogLUTData2 = 0xEA,
+			FogLUTData3 = 0xEB,
+			FogLUTData4 = 0xEC,
+			FogLUTData5 = 0xED,
+			FogLUTData6 = 0xEE,
+			FogLUTData7 = 0xEF,
+
 			// Framebuffer registers
 			ColourOperation = 0x100,
 			BlendFunc = 0x101,
@@ -384,6 +396,12 @@ namespace PICA {
 		GreaterOrEqual = 7,
 	};
 
+	enum class FogMode : u32 {
+		Disabled = 0,
+		Fog = 5,
+		Gas = 7,
+	};
+
 	struct TexEnvConfig {
 		enum class Source : u8 {
 			PrimaryColor = 0x0,

include/PICA/shader_gen.hpp

@@ -24,6 +24,8 @@ namespace PICA::ShaderGen {
 		void compileLUTLookup(std::string& shader, const PICA::FragmentConfig& config, u32 lightIndex, u32 lutID);
 		bool isSamplerEnabled(u32 environmentID, u32 lutID);
 
+		void compileFog(std::string& shader, const PICA::FragmentConfig& config);
+
 	  public:
 		FragmentGenerator(API api, Language language) : api(api), language(language) {}
 		std::string generate(const PICA::FragmentConfig& config);

include/renderer_gl/renderer_gl.hpp

@@ -63,7 +63,7 @@ class RendererGL final : public Renderer {
 	OpenGL::VertexBuffer dummyVBO;
 
 	OpenGL::Texture screenTexture;
-	OpenGL::Texture lightLUTTexture;
+	OpenGL::Texture LUTTexture;
 	OpenGL::Framebuffer screenFramebuffer;
 	OpenGL::Texture blankTexture;
 	// The "default" vertex shader to use when using specialized shaders but not PICA vertex shader -> GLSL recompilation
@@ -90,6 +90,7 @@ class RendererGL final : public Renderer {
 	void setupUbershaderTexEnv();
 	void bindTexturesToSlots();
 	void updateLightingLUT();
+	void updateFogLUT();
 	void initGraphicsContextInternal();
 
   public:

src/core/PICA/gpu.cpp

@@ -74,6 +74,9 @@ void GPU::reset() {
 	lightingLUT.fill(0);
 	lightingLUTDirty = true;
 
+	fogLUT.fill(0);
+	fogLUTDirty = true;
+
 	totalAttribCount = 0;
 	fixedAttribMask = 0;
 	fixedAttribIndex = 0;

src/core/PICA/regs.cpp

@@ -135,6 +135,21 @@ void GPU::writeInternalReg(u32 index, u32 value, u32 mask) {
 			break;
 		}
 
+		case FogLUTData0:
+		case FogLUTData1:
+		case FogLUTData2:
+		case FogLUTData3:
+		case FogLUTData4:
+		case FogLUTData5:
+		case FogLUTData6:
+		case FogLUTData7: {
+			const uint32_t index = regs[FogLUTIndex] & 127;
+			fogLUT[index] = value;
+			fogLUTDirty = true;
+			regs[FogLUTIndex] = (index + 1) & 127;
+			break;
+		}
+
 		case LightingLUTData0:
 		case LightingLUTData1:
 		case LightingLUTData2:

src/core/PICA/shader_gen_glsl.cpp

@@ -130,7 +130,7 @@ std::string FragmentGenerator::generate(const FragmentConfig& config) {
 		uniform sampler2D u_tex0;
 		uniform sampler2D u_tex1;
 		uniform sampler2D u_tex2;
-		uniform sampler2D u_tex_lighting_lut;
+		uniform sampler2D u_tex_luts;
 	)";
 
 	ret += uniformDefinition;
@@ -144,7 +144,7 @@ std::string FragmentGenerator::generate(const FragmentConfig& config) {
 			}
 
 			float lutLookup(uint lut, int index) {
-				return texelFetch(u_tex_lighting_lut, ivec2(index, int(lut)), 0).r;
+				return texelFetch(u_tex_luts, ivec2(index, int(lut)), 0).r;
 			}
 
 			vec3 regToColor(uint reg) {
@@ -194,6 +194,8 @@ std::string FragmentGenerator::generate(const FragmentConfig& config) {
 		compileTEV(ret, i, config);
 	}
 
+	compileFog(ret, config);
+
 	applyAlphaTest(ret, config);
 
 	ret += "fragColor = combinerOutput;\n}"; // End of main function
@@ -652,4 +654,27 @@ void FragmentGenerator::compileLUTLookup(std::string& shader, const PICA::Fragme
 			shader += "lut_lookup_result *= " + std::to_string(scales[scale]) + ";\n";
 		}
 	}
+}
+
+void FragmentGenerator::compileFog(std::string& shader, const PICA::FragmentConfig& config) {
+	if (config.fogConfig.mode != FogMode::Fog) {
+		return;
+	}
+
+	float r = config.fogConfig.fogColorR / 255.0f;
+	float g = config.fogConfig.fogColorG / 255.0f;
+	float b = config.fogConfig.fogColorB / 255.0f;
+
+	if (config.fogConfig.flipDepth) {
+		shader += "float fog_index = (1.0 - depth) * 128.0;\n";
+	} else {
+		shader += "float fog_index = depth * 128.0;\n";
+	}
+
+	shader += "float clamped_index = clamp(floor(fog_index), 0.0, 127.0);";
+	shader += "float delta = fog_index - clamped_index;";
+	shader += "vec3 fog_color = vec3(" + std::to_string(r) + ", " + std::to_string(g) + ", " + std::to_string(b) + ");";
+	shader += "vec2 value = texelFetch(u_tex_luts, ivec2(int(clamped_index), 24), 0).rg;"; // fog LUT is past the light LUTs
+	shader += "float fog_factor = clamp(value.r + value.g * delta, 0.0, 1.0);";
+	shader += "combinerOutput.rgb = mix(fog_color, combinerOutput.rgb, fog_factor);";
 }