Implemented ShaderProgramBuilder

CMakeLists.txt

@@ -7,3 +7,4 @@ find_package(glfw3 CONFIG REQUIRED)
 find_package(glm CONFIG REQUIRED)
 
 add_subdirectory(./source/app)
+add_subdirectory(./source/shader)

source/app/CMakeLists.txt

@@ -13,4 +13,5 @@ target_link_libraries(${PROJECT_NAME}
     GLEW::GLEW
     glfw
     glm::glm
+    UglyShaderLib
 )

source/app/src/App.cpp

@@ -6,6 +6,7 @@
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
 
+#include "ShaderProgramBuilder.hpp"
 
 int App::main(std::vector<std::string> &args) {
     auto app = App{};
@@ -57,9 +58,9 @@ App::~App() {
 
 void App::game_loop() {
     float vertices[] = {
-        .0f, .5f,
-        .5f, -.5f,
-        -.5f, -.5f
+        .0f, .5f, 1.f, 0.f, 0.f,
+        .5f, -.5f, 0.f, 1.f, 0.f,
+        -.5f, -.5f, 0.f, 0.f, 1.f
     };
 
     GLuint vbo;
@@ -70,56 +71,38 @@ void App::game_loop() {
     auto vertexSource = R"glsl(
         #version 150 core
         in vec2 position;
-        void main() { gl_Position = vec4(position, 0.0, 1.0); }
+        in vec3 color;
+        out vec3 _color;
+        void main() { _color = color; gl_Position = vec4(position, 0.0, 1.0); }
     )glsl";
 
-    GLint status;
-    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
-    glShaderSource(vertexShader, 1, &vertexSource, NULL);
-    glCompileShader(vertexShader);
-    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
-    if(!status) {
-        error_callback_s(GLFW_NO_ERROR, "glShaderSource() failed");
-    }
-
     auto fragmentSource = R"glsl(
         #version 150 core
-        uniform vec3 triangleColor;
+        in vec3 _color;
         out vec4 color;
-        void main() { color = vec4(triangleColor, 1.0); }
+        void main() { color = vec4(_color, 1.0); }
     )glsl";
 
-    
-    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
-    glShaderSource(fragmentShader, 1, &fragmentSource, NULL);
-    glCompileShader(fragmentShader);
-    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &status);
-    if(!status) {
-        error_callback_s(GLFW_NO_ERROR, "glShaderSource() failed");
-    }
-
-    GLuint shaderProgram = glCreateProgram();
-    glAttachShader(shaderProgram, vertexShader);
-    glAttachShader(shaderProgram, fragmentShader);
-    glLinkProgram(shaderProgram);
+    GLuint shaderProgram = ugly::ShaderProgramBuilder{}
+        .attachFromMemory(GL_VERTEX_SHADER, vertexSource)
+        .attachFromMemory(GL_FRAGMENT_SHADER, fragmentSource)
+        .link();
     glUseProgram(shaderProgram);
 
     GLuint vao;
     glGenVertexArrays(1, &vao);
     glBindVertexArray(vao);
-    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 5*sizeof(float), 0);
     glEnableVertexAttribArray(0);
-    
-    auto start = glfwGetTime();
+    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void*)(2*sizeof(float)));
+    glEnableVertexAttribArray(1);
 
     while(!glfwWindowShouldClose(mpWindow)) {
         glfwPollEvents();
 
+        glClear(GL_COLOR_BUFFER_BIT);
         glDrawArrays(GL_TRIANGLES, 0, 3);
 
-        auto now = glfwGetTime();
-        glUniform3f(glGetUniformLocation(shaderProgram, "triangleColor"), (sin(now-start) + 1.0f) / 2.0f, 0.0f, 0.0f);
-
         glfwSwapBuffers(mpWindow);
     }
 }

source/shader/CMakeLists.txt

@@ -0,0 +1,14 @@
+project(UglyShaderLib)
+
+add_library(${PROJECT_NAME}
+    ./src/ShaderProgramBuilder.cpp
+)
+
+target_include_directories(${PROJECT_NAME}
+    PUBLIC ./include
+    PRIVATE ./src
+)
+
+target_link_libraries(${PROJECT_NAME}
+    GLEW::GLEW
+)

source/shader/include/ShaderProgramBuilder.hpp

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <stdexcept>
+
+#include <GL/glew.h>
+
+namespace ugly{
+
+class ShaderProgramBuilder {
+public:
+    class Error: public std::runtime_error{
+    public:
+        using std::runtime_error::runtime_error;
+    };
+
+public:
+    ShaderProgramBuilder();
+    ~ShaderProgramBuilder();
+    void reset();
+    ShaderProgramBuilder &attachFromMemory(GLenum type, const GLchar *string, GLint length = 0);
+    ShaderProgramBuilder &attachFromFile(GLenum type, const char *filename);
+    GLuint link();
+
+private:
+    GLuint mProgram;
+};
+
+}

source/shader/src/ShaderProgramBuilder.cpp

@@ -0,0 +1,73 @@
+#include "ShaderProgramBuilder.hpp"
+
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <utility>
+
+
+ugly::ShaderProgramBuilder::ShaderProgramBuilder():
+    mProgram{glCreateProgram()} {
+}
+
+
+ugly::ShaderProgramBuilder::~ShaderProgramBuilder() {
+    if(mProgram != 0) {
+        glDeleteProgram(mProgram);
+    }
+}
+
+
+void ugly::ShaderProgramBuilder::reset() {
+    using namespace std;
+    swap(*this, ShaderProgramBuilder{});
+}
+
+
+ugly::ShaderProgramBuilder &ugly::ShaderProgramBuilder::attachFromMemory(GLenum type, const GLchar *string, GLint length) {
+    auto shader = glCreateShader(type);
+    glShaderSource(shader, 1, &string, length != 0 ? &length : NULL);
+    glCompileShader(shader);
+
+    GLint status;
+    glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
+    if(status != GL_TRUE) {
+        char buf[512];
+        glGetShaderInfoLog(shader, 512, NULL, buf);
+        glDeleteShader(shader);
+        std::cerr << "Failed to compile shader:\n\t" << buf << '\n';
+        throw Error{"shader failed to compile"};
+    }
+
+    glAttachShader(mProgram, shader);
+    glDeleteShader(shader);
+    return *this;
+}
+
+
+ugly::ShaderProgramBuilder &ugly::ShaderProgramBuilder::attachFromFile(GLenum type, const char *filename) {
+    auto file = std::ifstream{filename};
+    file.exceptions(std::ios_base::badbit);
+    std::ostringstream ss;
+    ss << file.rdbuf();
+    return attachFromMemory(type, ss.str().c_str());
+}
+
+
+GLuint ugly::ShaderProgramBuilder::link() {
+    glLinkProgram(mProgram);
+    
+    GLint status;
+    glGetProgramiv(mProgram, GL_LINK_STATUS, &status);
+    if(status != GL_TRUE) {
+        char buf[512];
+        glGetProgramInfoLog(mProgram, 512, NULL, buf);
+        std::cerr << "Failed to link program:\n\t" << buf << '\n';
+        throw Error{"program failed to link"};
+    }
+
+    auto result = mProgram;
+    mProgram = 0;
+    reset();
+    return result;
+}