gl_rasterizer: implement custom clip plane

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -169,6 +169,8 @@ RasterizerOpenGL::RasterizerOpenGL() : shader_dirty(true) {
     glTexBuffer(GL_TEXTURE_BUFFER, GL_RGBA32F, proctex_diff_lut_buffer.handle);
 
     // Sync fixed function OpenGL state
+    SyncClipEnabled();
+    SyncClipCoef();
     SyncCullMode();
     SyncBlendEnabled();
     SyncBlendFuncs();
@@ -401,6 +403,18 @@ void RasterizerOpenGL::NotifyPicaRegisterChanged(u32 id) {
         SyncCullMode();
         break;
 
+    // Clipping plane
+    case PICA_REG_INDEX(rasterizer.clip_enable):
+        SyncClipEnabled();
+        break;
+
+    case PICA_REG_INDEX_WORKAROUND(rasterizer.clip_coef[0], 0x48):
+    case PICA_REG_INDEX_WORKAROUND(rasterizer.clip_coef[1], 0x49):
+    case PICA_REG_INDEX_WORKAROUND(rasterizer.clip_coef[2], 0x4a):
+    case PICA_REG_INDEX_WORKAROUND(rasterizer.clip_coef[3], 0x4b):
+        SyncClipCoef();
+        break;
+
     // Depth modifiers
     case PICA_REG_INDEX(rasterizer.viewport_depth_range):
         SyncDepthScale();
@@ -1280,6 +1294,20 @@ void RasterizerOpenGL::SetShader() {
     }
 }
 
+void RasterizerOpenGL::SyncClipEnabled() {
+    state.clip_distance[1] = Pica::g_state.regs.rasterizer.clip_enable != 0;
+}
+
+void RasterizerOpenGL::SyncClipCoef() {
+    const auto raw_clip_coef = Pica::g_state.regs.rasterizer.GetClipCoef();
+    const GLvec4 new_clip_coef = {raw_clip_coef.x.ToFloat32(), raw_clip_coef.y.ToFloat32(),
+                                  raw_clip_coef.z.ToFloat32(), raw_clip_coef.w.ToFloat32()};
+    if (new_clip_coef != uniform_block_data.data.clip_coef) {
+        uniform_block_data.data.clip_coef = new_clip_coef;
+        uniform_block_data.dirty = true;
+    }
+}
+
 void RasterizerOpenGL::SyncCullMode() {
     const auto& regs = Pica::g_state.regs;
 

src/video_core/renderer_opengl/gl_rasterizer.h

@@ -151,14 +151,21 @@ private:
         LightSrc light_src[8];
         alignas(16) GLvec4 const_color[6]; // A vec4 color for each of the six tev stages
         alignas(16) GLvec4 tev_combiner_buffer_color;
+        alignas(16) GLvec4 clip_coef;
     };
 
     static_assert(
-        sizeof(UniformData) == 0x460,
+        sizeof(UniformData) == 0x470,
         "The size of the UniformData structure has changed, update the structure in the shader");
     static_assert(sizeof(UniformData) < 16384,
                   "UniformData structure must be less than 16kb as per the OpenGL spec");
 
+    /// Syncs the clip enabled status to match the PICA register
+    void SyncClipEnabled();
+
+    /// Syncs the clip coefficients to match the PICA register
+    void SyncClipCoef();
+
     /// Sets the OpenGL shader in accordance with the current PICA register state
     void SetShader();
 

src/video_core/renderer_opengl/gl_shader_gen.cpp

@@ -24,6 +24,42 @@ using TevStageConfig = TexturingRegs::TevStageConfig;
 
 namespace GLShader {
 
+static const std::string UniformBlockDef = R"(
+#define NUM_TEV_STAGES 6
+#define NUM_LIGHTS 8
+
+struct LightSrc {
+    vec3 specular_0;
+    vec3 specular_1;
+    vec3 diffuse;
+    vec3 ambient;
+    vec3 position;
+    vec3 spot_direction;
+    float dist_atten_bias;
+    float dist_atten_scale;
+};
+
+layout (std140) uniform shader_data {
+    vec2 framebuffer_scale;
+    int alphatest_ref;
+    float depth_scale;
+    float depth_offset;
+    int scissor_x1;
+    int scissor_y1;
+    int scissor_x2;
+    int scissor_y2;
+    vec3 fog_color;
+    vec2 proctex_noise_f;
+    vec2 proctex_noise_a;
+    vec2 proctex_noise_p;
+    vec3 lighting_global_ambient;
+    LightSrc light_src[NUM_LIGHTS];
+    vec4 const_color[NUM_TEV_STAGES];
+    vec4 tev_combiner_buffer_color;
+    vec4 clip_coef;
+};
+)";
+
 PicaShaderConfig PicaShaderConfig::BuildFromRegs(const Pica::Regs& regs) {
     PicaShaderConfig res;
 
@@ -1008,8 +1044,6 @@ std::string GenerateFragmentShader(const PicaShaderConfig& config) {
 
     std::string out = R"(
 #version 330 core
-#define NUM_TEV_STAGES 6
-#define NUM_LIGHTS 8
 
 in vec4 primary_color;
 in vec2 texcoord[3];
@@ -1021,36 +1055,6 @@ in vec4 gl_FragCoord;
 
 out vec4 color;
 
-struct LightSrc {
-    vec3 specular_0;
-    vec3 specular_1;
-    vec3 diffuse;
-    vec3 ambient;
-    vec3 position;
-    vec3 spot_direction;
-    float dist_atten_bias;
-    float dist_atten_scale;
-};
-
-layout (std140) uniform shader_data {
-    vec2 framebuffer_scale;
-    int alphatest_ref;
-    float depth_scale;
-    float depth_offset;
-    int scissor_x1;
-    int scissor_y1;
-    int scissor_x2;
-    int scissor_y2;
-    vec3 fog_color;
-    vec2 proctex_noise_f;
-    vec2 proctex_noise_a;
-    vec2 proctex_noise_p;
-    vec3 lighting_global_ambient;
-    LightSrc light_src[NUM_LIGHTS];
-    vec4 const_color[NUM_TEV_STAGES];
-    vec4 tev_combiner_buffer_color;
-};
-
 uniform sampler2D tex[3];
 uniform samplerBuffer lighting_lut;
 uniform samplerBuffer fog_lut;
@@ -1059,7 +1063,11 @@ uniform samplerBuffer proctex_color_map;
 uniform samplerBuffer proctex_alpha_map;
 uniform samplerBuffer proctex_lut;
 uniform samplerBuffer proctex_diff_lut;
+)";
+
+    out += UniformBlockDef;
 
+    out += R"(
 // Rotate the vector v by the quaternion q
 vec3 quaternion_rotate(vec4 q, vec3 v) {
     return v + 2.0 * cross(q.xyz, cross(q.xyz, v) + q.w * v);
@@ -1190,6 +1198,12 @@ out float texcoord0_w;
 out vec4 normquat;
 out vec3 view;
 
+)";
+
+    out += UniformBlockDef;
+
+    out += R"(
+
 void main() {
     primary_color = vert_color;
     texcoord[0] = vert_texcoord0;
@@ -1200,7 +1214,7 @@ void main() {
     view = vert_view;
     gl_Position = vert_position;
     gl_ClipDistance[0] = -vert_position.z; // fixed PICA clipping plane z <= 0
-    // TODO (wwylele): calculate gl_ClipDistance[1] from user-defined clipping plane
+    gl_ClipDistance[1] = dot(clip_coef, vert_position);
 }
 )";