From 3b734f0d6b9e28c1f2c4ae54e3f46e573e02f4a5 Mon Sep 17 00:00:00 2001
From: Andreas Grois <andi@grois.info>
Date: Fri, 9 Mar 2018 21:36:10 +0100
Subject: Initial Commit

---
 BuddhaTest/src/BuddhaTest.cpp | 124 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 BuddhaTest/src/BuddhaTest.cpp

(limited to 'BuddhaTest/src/BuddhaTest.cpp')

diff --git a/BuddhaTest/src/BuddhaTest.cpp b/BuddhaTest/src/BuddhaTest.cpp
new file mode 100644
index 0000000..fcbf3bf
--- /dev/null
+++ b/BuddhaTest/src/BuddhaTest.cpp
@@ -0,0 +1,124 @@
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include <Helpers.h>
+#include <iostream>
+#include <vector>
+
+void error_callback(int error, const char* description)
+{
+	std::cerr << "Error: " << description << std::endl;
+}
+
+int main()
+{
+    unsigned int bufferWidth = 640;
+    unsigned int bufferHeight = 480;
+
+
+	GLFWwindow* window;
+
+	/* Initialize the library */
+	if (!glfwInit())
+		return -1;
+
+	glfwSetErrorCallback(error_callback);
+
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+
+	/* Create a windowed mode window and its OpenGL context */
+    window = glfwCreateWindow(640, 480, "Buddhabrot", NULL, NULL);
+	if (!window)
+	{
+		std::cerr << "Failed to create OpenGL 4.3 core context. We do not support compatibility contexts." << std::endl;
+		glfwTerminate();
+		return -1;
+	}
+
+	/* Make the window's context current */
+	glfwMakeContextCurrent(window);
+	gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);
+
+	GLuint VertexArrayID;
+	glGenVertexArrays(1, &VertexArrayID);
+	glBindVertexArray(VertexArrayID);
+
+	const GLfloat g_vertex_buffer_data[] = {
+		-1.0f, -1.0f, 0.0f,
+		1.0f, -1.0f, 0.0f,
+		-1.0f,  1.0f, 0.0f,
+		1.0f, 1.0f, 0.0f
+	};
+
+	GLuint vertexbuffer;
+	glGenBuffers(1, &vertexbuffer);
+	glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
+
+
+	GLuint drawBuffer;
+	glGenBuffers(1, &drawBuffer);
+	glBindBuffer(GL_SHADER_STORAGE_BUFFER, drawBuffer);
+    {
+        const unsigned int pixelCount{(bufferWidth * bufferHeight)*3}; //*3 -> RGB
+        const unsigned int integerCount = pixelCount + 2; //first two elements in buffer: width/height.
+        std::vector<uint32_t> initializeBuffer(integerCount,0);
+        initializeBuffer[0] = bufferWidth;
+        initializeBuffer[1] = bufferHeight;
+        glBufferData(GL_SHADER_STORAGE_BUFFER, 4 * integerCount, initializeBuffer.data(), GL_DYNAMIC_COPY);
+    }
+	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 2, drawBuffer);
+	glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+
+	// Create and compile our GLSL program from the shaders
+	GLuint VertexAndFragmentShaders = Helpers::LoadShaders("Shaders/BuddhaVertex.glsl", "Shaders/BuddhaFragment.glsl");
+	//Do the same for the compute shader:
+	GLuint ComputeShader = Helpers::LoadComputeShader("Shaders/BuddhaCompute.glsl");
+
+    uint32_t iterationCount{0};
+    glUseProgram(ComputeShader);
+    GLint iterationCountUniformHandle = glGetUniformLocation(ComputeShader, "iterationCount");
+
+    glClearColor(0.0f, 0.0f, 0.4f, 0.0f);
+
+	/* Loop until the user closes the window */
+	while (!glfwWindowShouldClose(window))
+	{
+		//let the compute shader do something
+		glUseProgram(ComputeShader);
+        //increase iterationCount, which is used for pseudo random generation
+        glUniform1ui(iterationCountUniformHandle,++iterationCount);
+		glDispatchCompute(1920, 1080, 1);
+
+        //before reading the values in the ssbo, we need a memory barrier:
+        glMemoryBarrier(GL_SHADER_STORAGE_BARRIER_BIT); //I hope this is the correct (and only required) bit
+
+		/* Render here */
+		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+		glUseProgram(VertexAndFragmentShaders);
+		
+		glEnableVertexAttribArray(0);
+		glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
+		glVertexAttribPointer(
+			0,                  // attribute 0. No particular reason for 0, but must match the layout in the shader.
+			3,                  // size
+			GL_FLOAT,           // type
+			GL_FALSE,           // normalized?
+			0,                  // stride
+			(void*)0            // array buffer offset
+		);
+		// Draw the triangle !
+		glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); // Triangle strip with 4 vertices -> quad.
+		glDisableVertexAttribArray(0);
+
+		/* Swap front and back buffers */
+		glfwSwapBuffers(window);
+
+		/* Poll for and process events */
+		glfwPollEvents();
+	}
+
+	glfwTerminate();
+	return 0;
+}
-- 
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