From a5c84e31d21756d02032be88532f0909f8cee476 Mon Sep 17 00:00:00 2001
From: Vitor Fernandes <vitor.fernandes@jumo.world>
Date: Sun, 21 Jun 2020 22:17:44 +0100
Subject: [PATCH] More on shaders to classes

---
 src/opengl/Shader.cpp | 22 +++++++++++++++++-----
 src/opengl/Shader.h   |  2 ++
 src/opengl/gl1.cpp    | 16 +++++++++++-----
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/src/opengl/Shader.cpp b/src/opengl/Shader.cpp
index 30535dd..4ea007c 100644
--- a/src/opengl/Shader.cpp
+++ b/src/opengl/Shader.cpp
@@ -11,29 +11,41 @@
 Shader::Shader(const std::string &filepath)
     : m_FilePath(filepath), m_RendererID(0)
 {
-  //ShaderProgramSource source = ParseShader(m_FilePath);
-  //m_RendererID = CreateShader(source.VertexSource, source.FragmentSource);
+  ShaderProgramSource source = ParseShader(m_FilePath);
+  m_RendererID = CreateShader(source.VertexSource, source.FragmentSource);
 }
 
-
 Shader::~Shader()
 {
 }
 
 void Shader::Bind()
 {
+  GLCall(glUseProgram(m_RendererID));
 }
 
 void Shader::Unbind()
 {
+  GLCall(glUseProgram(0));
 }
 
 //Set uniforms
 void Shader::SetUniform4f(const std::string &name, float v0, float v1, float v2, float v3)
 {
+  GLCall(glUniform4f(GetUniformLocation(name), v0, v1, v2, v3));
 }
 unsigned int Shader::GetUniformLocation(const std::string &name)
 {
+  if (m_UniformLocationCache.find(name) != m_UniformLocationCache.end())
+    return m_UniformLocationCache[name];
+
+  GLCall(unsigned int location = glGetUniformLocation(m_RendererID, name.c_str()));
+
+  if (location == -1)
+    LOG("Warning: uniform" << name << " doesn't exist");
+
+  m_UniformLocationCache[name] = location;
+  return location;
 }
 
 /**
@@ -72,9 +84,9 @@ unsigned int Shader::CompileShader(unsigned int type, const std::string &source)
   {
     int length;
     glGetShaderiv(id, GL_INFO_LOG_LENGTH, &length);
-    
+
     LOG("Length: " << length);
-    
+
     char *message = (char *)malloc(length * sizeof(char));
     glGetShaderInfoLog(id, length, &length, message);
 
diff --git a/src/opengl/Shader.h b/src/opengl/Shader.h
index 679d2b6..ca2c34b 100644
--- a/src/opengl/Shader.h
+++ b/src/opengl/Shader.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <string>
+#include <unordered_map>
 
 struct ShaderProgramSource
 {
@@ -14,6 +15,7 @@ struct ShaderProgramSource
 class Shader
 {
 private:
+  std::unordered_map<std::string,unsigned int> m_UniformLocationCache;
   unsigned int m_RendererID;
   std::string m_FilePath;
   ShaderProgramSource ParseShader(const std::string &filepath);
diff --git a/src/opengl/gl1.cpp b/src/opengl/gl1.cpp
index 6204462..664253f 100644
--- a/src/opengl/gl1.cpp
+++ b/src/opengl/gl1.cpp
@@ -12,7 +12,7 @@
 #include "VertexArray.h"
 #include "utils.h"
 
-//const std::string SHADERS_PATH = "src/opengl/res/shaders/Basic.shader";
+const std::string SHADERS_PATH = "src/opengl/res/shaders/Basic.shader";
 
 int main(void)
 {
@@ -70,11 +70,14 @@ int main(void)
 
     IndexBuffer ib(indexes,6);
 
+    Shader shader(SHADERS_PATH);
+    shader.Bind();
+    shader.SetUniform4f("u_Color",0.2f, 0.3f, 0.8f, 1.0f);
 
-    //Find the shader uniform color
-    //int uniform_location = glGetUniformLocation(shader, "u_color");
-
-    //if (uniform_location == -1) LOG("Error fetching uniform location");
+    va.Unbind();
+    vb.Unbind();
+    ib.Unbind();
+    shader.Unbind();  
 
     float red = 0.0f;
     float increment = 0.05f;
@@ -104,6 +107,9 @@ int main(void)
 
         //GLCall(glDrawElements(GL_TRIANGLES, 6 * sizeof(uint), GL_UNSIGNED_INT, nullptr));
 
+        shader.Bind();
+        shader.SetUniform4f("u_Color",red, 0.3f, 0.8f, 1.0f);
+
         if (red > 1.0f)
             increment = -0.05f;
         else if (red < 0.0f)