From a8feed9d7951c9a947562ed687c704851a31ea9b Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Mon, 21 May 2018 14:35:43 +0200
Subject: Fix VAO, VBO setup, compute shader coupling

---
 src/main.cc | 113 +++++++++++++++++++++++-------------------------------------
 1 file changed, 43 insertions(+), 70 deletions(-)

(limited to 'src/main.cc')

diff --git a/src/main.cc b/src/main.cc
index c6945fb..7b4415b 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -4,8 +4,6 @@
 #include <glm/glm.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 
-#include <vector>
-#include <iostream>
 #include <random>
 #include <chrono>
 #include <memory>
@@ -13,6 +11,7 @@
 #include "graphic_shader.h"
 #include "compute_shader.h"
 #include "texture_buffer.h"
+#include "particle_vertex_buffer.h"
 
 #include "shader/vertex.glsl"
 #include "shader/fragment.glsl"
@@ -24,7 +23,9 @@ int window_width  = 800;
 int window_height = 600;
 float world_width, world_height;
 glm::mat4 MVP;
-std::unique_ptr<TextureBuffer> textureBuffer;
+
+std::unique_ptr<TextureBuffer>        textureBuffer;
+std::unique_ptr<ParticleVertexBuffer> particleBuffer;
 
 void updateMVP() {
 	world_width  = 20.f;
@@ -101,48 +102,38 @@ int main() {
 
 	updateMVP();
 
-	textureBuffer = std::make_unique<TextureBuffer>(window_width, window_height);
-
-	{
-		auto guard = textureBuffer->use();
-
-		glClearColor(0.0f, 0.0f, 0.4f, 0.0f);
-	}
-
 	GraphicShader sceneShader(VERTEX_SHADER_CODE, FRAGMENT_SHADER_CODE);
-	sceneShader.setUniform("MVP", MVP);
-
-	ComputeShader computeShader(COMPUTE_SHADER_CODE);
-
-	auto vertex_buffer_data = makeInitialParticles(particle_count);
+	GraphicShader displayShader(R"(
+		#version 330 core
+		layout (location = 0) in vec2 screen_vertex;
+		layout (location = 1) in vec2 texture_vertex;
+		out vec2 TexCoords;
 
-	GLuint VertexArrayID;
-	GLuint VertexBufferID;
+		void main() {
+			gl_Position = vec4(screen_vertex, 0.0, 1.0);
+			TexCoords = texture_vertex;
+		}
+		)", R"(
+		#version 330 core
+		out vec4 FragColor;
+		in vec2 TexCoords;
+		uniform sampler2D screen_texture;
 
-	{
-		auto guard = textureBuffer->use();
+		void main() {
+			FragColor = texture(screen_texture, TexCoords);
+		}
+		)");
 
-		glGenVertexArrays(1, &VertexArrayID);
-		glBindVertexArray(VertexArrayID);
-		glEnableVertexAttribArray(0);
+	sceneShader.setUniform("MVP", MVP);
+	displayShader.setUniform("screen_texture", 0);
 
-		glGenBuffers(1, &VertexBufferID);
-		glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, VertexBufferID);
+	textureBuffer = std::make_unique<TextureBuffer>(window_width, window_height);
+	particleBuffer = std::make_unique<ParticleVertexBuffer>(
+		makeInitialParticles(particle_count));
 
-		glBufferData(
-			GL_SHADER_STORAGE_BUFFER,
-			vertex_buffer_data.size() * sizeof(GLfloat),
-			vertex_buffer_data.data(),
-			GL_STATIC_DRAW
-		);
-	}
+	ComputeShader computeShader(COMPUTE_SHADER_CODE);
+	computeShader.workOn(particleBuffer->getBuffer());
 
-	GLuint QuadVertexArrayID;
-	glGenVertexArrays(1, &QuadVertexArrayID);
-	glBindVertexArray(QuadVertexArrayID);
-	GLuint QuadVertexBufferID;
-	glGenBuffers(1, &QuadVertexBufferID);
-	glBindBuffer(GL_ARRAY_BUFFER, QuadVertexBufferID);
 	const std::vector<GLfloat> quad_buffer_data{
 		-1.f,  1.f, 0.f, 1.f,
 		-1.f, -1.f, 0.f, 0.f,
@@ -152,36 +143,26 @@ int main() {
 		 1.f, -1.f, 1.f, 0.f,
 		 1.f,  1.f, 1.f, 1.f
 	};
+
+	GLuint QuadVertexArrayID;
+	GLuint QuadVertexBufferID;
+
+	glGenVertexArrays(1, &QuadVertexArrayID);
+	glGenBuffers(1, &QuadVertexBufferID);
+
+	glBindVertexArray(QuadVertexArrayID);
+	glBindBuffer(GL_ARRAY_BUFFER, QuadVertexBufferID);
 	glBufferData(
 		GL_ARRAY_BUFFER,
 		quad_buffer_data.size() * sizeof(GLfloat),
 		quad_buffer_data.data(),
 		GL_STATIC_DRAW
 	);
+
 	glEnableVertexAttribArray(0);
+	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4*sizeof(GLfloat), (void*)0);
 	glEnableVertexAttribArray(1);
-
-	GraphicShader displayShader(R"(
-		#version 330 core
-		layout (location = 0) in vec2 screen_vertex;
-		layout (location = 1) in vec2 texture_vertex;
-		out vec2 TexCoords;
-
-		void main() {
-			gl_Position = vec4(screen_vertex, 0.0, 1.0);
-			TexCoords = texture_vertex;
-		}
-		)", R"(
-		#version 330 core
-		out vec4 FragColor;
-		in vec2 TexCoords;
-		uniform sampler2D screen_texture;
-
-		void main() {
-			FragColor = texture(screen_texture, TexCoords);
-		}
-		)");
-	displayShader.setUniform("screen_texture", 0);
+	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4*sizeof(GLfloat), (void*)(2*sizeof(GLfloat)));
 
 	auto lastFrame = std::chrono::high_resolution_clock::now();
 
@@ -204,18 +185,14 @@ int main() {
 
 			sceneShader.setUniform("MVP", MVP);
 
-			glBindBuffer(GL_ARRAY_BUFFER, VertexBufferID);
-			glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
-			glDrawArrays(GL_POINTS, 0, 3*particle_count);
+			particleBuffer->draw();
 		}
 
 		{
 			auto guard = displayShader.use();
 
+			glBindVertexArray(QuadVertexArrayID);
 			glBindTexture(GL_TEXTURE_2D, textureBuffer->getTexture());
-			glBindBuffer(GL_ARRAY_BUFFER, QuadVertexBufferID);
-			glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4*sizeof(GLfloat), (void*)0);
-			glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4*sizeof(GLfloat), (void*)(2*sizeof(GLfloat)));
 
 			glClear(GL_COLOR_BUFFER_BIT);
 			glDrawArrays(GL_TRIANGLES, 0, 6);
@@ -227,10 +204,6 @@ int main() {
 	while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS &&
 	       glfwWindowShouldClose(window) == 0 );
 
-	glDeleteBuffers(1, &VertexBufferID);
-	glDisableVertexAttribArray(0);
-	glDeleteVertexArrays(1, &VertexArrayID);
-
 	glfwTerminate();
 
 	return 0;
-- 
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