From 454ea72a8556992e0c279ba4cb5584ee327ac2e3 Mon Sep 17 00:00:00 2001
From: Martin Felis <martin@fysx.org>
Date: Tue, 27 Feb 2018 23:31:13 +0100
Subject: [PATCH] Added OpenGL error logging, trying to draw colored lines...

---
 data/shaders/vs_simple.glsl |  4 ++--
 src/main.cc                 | 18 ++++++++++++++++++
 src/modules/RenderModule.cc | 15 +++++++++------
 src/modules/RenderUtils.cc  |  3 +--
 4 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/data/shaders/vs_simple.glsl b/data/shaders/vs_simple.glsl
index 5051b16..573f5f8 100644
--- a/data/shaders/vs_simple.glsl
+++ b/data/shaders/vs_simple.glsl
@@ -1,8 +1,8 @@
 #version 150 core
 #extension GL_ARB_explicit_attrib_location : require
 
-layout(location = 0) in vec3 inCoord;
-layout(location = 1) in vec3 inColor;
+in vec3 inCoord;
+in vec3 inColor;
 
 uniform mat4 uModelViewProj;
 
diff --git a/src/main.cc b/src/main.cc
index c41ee95..6302877 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -43,6 +43,20 @@ static void error_callback(int error, const char* description)
     fprintf(stderr, "Error (%d): %s\n", error, description);
 }
 
+static void opengl_error_callback(
+		GLenum source,
+		GLenum type,
+		GLuint id,
+		GLenum severity,
+		GLsizei length,
+		const GLchar* message,
+		const void* userParam )
+{
+	gLog ("OpenGL Error: %s type %0x%x, severity = 0x%x, message = %s",
+           ( type == GL_DEBUG_TYPE_ERROR ? "** GL ERROR **" : "" ),
+            type, severity, message );
+}
+
 static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
 {
     if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
@@ -117,6 +131,10 @@ int main(void)
 	std::cout << "OpenGL Version: " << glGetString(GL_VERSION) << endl;
 	std::cout << "GLSL Version  : " << glGetString(GL_SHADING_LANGUAGE_VERSION) << endl;
 
+	// During init, enable debug output
+	glEnable              ( GL_DEBUG_OUTPUT );
+	glDebugMessageCallback( (GLDEBUGPROC) opengl_error_callback, 0 );
+
 	// imgui initialization.
 	ImGui::CreateContext();
 	ImGuiIO& io = ImGui::GetIO(); (void)io;
diff --git a/src/modules/RenderModule.cc b/src/modules/RenderModule.cc
index cbecd92..6235d96 100644
--- a/src/modules/RenderModule.cc
+++ b/src/modules/RenderModule.cc
@@ -42,10 +42,10 @@ static const GLfloat g_textured_quad_vertex_buffer_data[] = {
 };
 
 static const GLfloat g_coordinate_system_vertex_buffer_data[] = {
-	0.0f, 0.0f, 0.0f,		1.0f, 0.0f, 0.0f,
-	1.0f, 0.0f, 0.0f,		1.0f, 0.0f, 0.0f,
-	0.0f, 0.0f, 0.0f,		0.0f, 1.0f, 0.0f,
-	0.0f, 1.0f, 0.0f,		0.0f, 1.0f, 0.0f,
+	0.0f, 0.0f, 0.0f,		255.0f, 0.0f, 0.0f,
+	1.0f, 0.0f, 0.0f,		255.0f, 0.0f, 0.0f,
+	0.0f, 0.0f, 0.0f,		0.0f, 255.0f, 0.0f,
+	0.0f, 1.0f, 0.0f,		0.0f, 255.0f, 0.0f,
 	0.0f, 0.0f, 0.0f,		0.0f, 0.0f, 1.0f,
 	0.0f, 0.0f, 1.0f,		0.0f, 0.0f, 1.0f
 };
@@ -180,7 +180,7 @@ void Camera::DrawGui() {
 //
 void Renderer::Initialize(int width, int height) {
 	mDefaultTexture.MakeGrid(128, Vector3f (0.8, 0.8f, 0.8f), Vector3f (0.2f, 0.2f, 0.2f));
-
+	
 	// Mesh
 	glGenVertexArrays(1, &mMesh.mVertexArrayId);
 	glBindVertexArray(mMesh.mVertexArrayId);
@@ -296,10 +296,13 @@ void Renderer::RenderGl() {
 //	glDrawArrays(GL_TRIANGLES, 0, 3);	// starting from vertex 0; 3 vertices total
 	glDisableVertexAttribArray(0);
 
+	glBindAttribLocation(mDefaultProgram.mProgramId, 0, "inCoord");
+	glBindAttribLocation(mDefaultProgram.mProgramId, 1, "inColor");
+
 	// Coordinate system
 	glBindVertexArray(mCoordinateSystem.mVertexArrayId);
 	glEnableVertexAttribArray(0);
-	glUniform4fv(muDefaultColor, 1, Vector4f(1.0f, 0.0f, 1.0f, 1.0f).data());
+	glUniform4fv(muDefaultColor, 1, Vector4f(1.0f, 0.0f, 0.0f, 1.0f).data());
 	glBindBuffer(GL_ARRAY_BUFFER, mCoordinateSystem.mVertexBuffer);
 	glVertexAttribPointer(
 			0,
diff --git a/src/modules/RenderUtils.cc b/src/modules/RenderUtils.cc
index aa9005a..0862c84 100644
--- a/src/modules/RenderUtils.cc
+++ b/src/modules/RenderUtils.cc
@@ -19,7 +19,7 @@ using namespace SimpleMath;
 //
 
 RenderProgram::~RenderProgram() {
-	if (mProgramId > 0)
+	if (mProgramId != -1)
 		glDeleteProgram(mProgramId);
 }
 
@@ -298,7 +298,6 @@ void Texture::MakeGrid(const int& size, const Vector3f &c1, const Vector3f &c2)
 		}
 	}
 
-
 	glGenTextures(1, &mTextureId);
 	glBindTexture(GL_TEXTURE_2D, mTextureId);