Merge pull request #450 from Subv/shader_link_error

GLRenderer: Log the shader source code when program linking fails.

src/video_core/renderer_opengl/gl_shader_util.h

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <string>
 #include <vector>
 #include <glad/glad.h>
 #include "common/assert.h"
@@ -11,6 +12,27 @@
 
 namespace GLShader {
 
+/**
+ * Utility function to log the source code of a list of shaders.
+ * @param shaders The OpenGL shaders whose source we will print.
+ */
+template <typename... T>
+void LogShaderSource(T... shaders) {
+    auto shader_list = {shaders...};
+
+    for (const auto& shader : shader_list) {
+        if (shader == 0)
+            continue;
+
+        GLint source_length;
+        glGetShaderiv(shader, GL_SHADER_SOURCE_LENGTH, &source_length);
+
+        std::string source(source_length, ' ');
+        glGetShaderSource(shader, source_length, nullptr, &source[0]);
+        NGLOG_INFO(Render_OpenGL, "Shader source {}", source);
+    }
+}
+
 /**
  * Utility function to create and compile an OpenGL GLSL shader
  * @param source String of the GLSL shader program
@@ -55,6 +77,11 @@ GLuint LoadProgram(bool separable_program, T... shaders) {
         }
     }
 
+    if (result == GL_FALSE) {
+        // There was a problem linking the shader, print the source for debugging purposes.
+        LogShaderSource(shaders...);
+    }
+
     ASSERT_MSG(result == GL_TRUE, "Shader not linked");
 
     ((shaders == 0 ? (void)0 : glDetachShader(program_id, shaders)), ...);