From acd89cf669a5fb18668f5cb5762a971b0ba42801 Mon Sep 17 00:00:00 2001
From: LaG1924 <12997935+LaG1924@users.noreply.github.com>
Date: Fri, 25 Jan 2019 08:46:05 +0500
Subject: Added Framebuffer class

---
 src/Framebuffer.cpp | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 src/Framebuffer.cpp

(limited to 'src/Framebuffer.cpp')

diff --git a/src/Framebuffer.cpp b/src/Framebuffer.cpp
new file mode 100644
index 0000000..7127a57
--- /dev/null
+++ b/src/Framebuffer.cpp
@@ -0,0 +1,125 @@
+#include "Framebuffer.hpp"
+#include "Shader.hpp"
+#include <string>
+#include "Utility.hpp"
+
+GLuint quadVao, quadVbo;
+Shader *quadShader = nullptr;
+
+Framebuffer::Framebuffer(unsigned int width, unsigned int height, bool createDepthStencilBuffer) : width(width), height(height) {
+	if (quadShader == nullptr) {
+		float quadVertices[] = {
+			// positions   // texCoords
+			-1.0f,  1.0f,  0.0f, 1.0f,
+			-1.0f, -1.0f,  0.0f, 0.0f,
+			 1.0f, -1.0f,  1.0f, 0.0f,
+
+			-1.0f,  1.0f,  0.0f, 1.0f,
+			 1.0f, -1.0f,  1.0f, 0.0f,
+			 1.0f,  1.0f,  1.0f, 1.0f
+		};
+
+		glGenVertexArrays(1, &quadVao);
+		glGenBuffers(1, &quadVbo);
+		glBindVertexArray(quadVao);
+		glBindBuffer(GL_ARRAY_BUFFER, quadVbo);
+		glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
+		glEnableVertexAttribArray(0);
+		glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
+		glEnableVertexAttribArray(1);
+		glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));
+		quadShader = new Shader("./shaders/fbo.vs", "./shaders/fbo.fs");
+		quadShader->Use();
+		glUniform1i(glGetUniformLocation(quadShader->Program, "inputTexture"), 1);
+		glActiveTexture(GL_TEXTURE1);
+		glCheckError();
+	}
+
+	glGenTextures(1, &texColor);
+	glBindTexture(GL_TEXTURE_2D, texColor);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glCheckError();
+
+	if (createDepthStencilBuffer) {
+		glGenRenderbuffers(1, &rboDepthStencil);
+		glBindRenderbuffer(GL_RENDERBUFFER, rboDepthStencil);
+		glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
+	}
+
+	glGenFramebuffers(1, &fbo);
+	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texColor, 0);
+	if(createDepthStencilBuffer)
+		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rboDepthStencil);
+	glCheckError();
+
+	GLenum framebufferStatus = glCheckFramebufferStatus(GL_FRAMEBUFFER);
+	if (framebufferStatus != GL_FRAMEBUFFER_COMPLETE)
+		throw std::runtime_error("Failed to initialize framebuffer: " + std::to_string(framebufferStatus));	
+}
+
+Framebuffer::~Framebuffer() {
+	if (rboDepthStencil)
+		glDeleteRenderbuffers(1, &rboDepthStencil);
+	if (texColor)
+		glDeleteTextures(1, &texColor);
+
+	glDeleteFramebuffers(1, &fbo);
+}
+
+void Framebuffer::Activate() {
+	glViewport(0, 0, width, height);
+	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+}
+
+void Framebuffer::RenderTo(Framebuffer &target) {
+	glBindFramebuffer(GL_FRAMEBUFFER, target.fbo);
+	glViewport(0, 0, target.width, target.height);
+	glBindVertexArray(quadVao);
+	glUseProgram(quadShader->Program);
+	glBindTexture(GL_TEXTURE_2D, texColor);
+	glDrawArrays(GL_TRIANGLES, 0, 6);
+}
+
+void Framebuffer::Resize(unsigned int newWidth, unsigned int newHeight) {
+	width = newWidth;
+	height = newHeight;
+	if (texColor) {
+		glBindTexture(GL_TEXTURE_2D, texColor);
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, newWidth, newHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+	}	
+	if (rboDepthStencil) {
+		glBindRenderbuffer(GL_RENDERBUFFER, rboDepthStencil);
+		glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
+	}
+}
+
+Framebuffer &Framebuffer::GetDefault()
+{
+	static char fboDefaultData[sizeof(Framebuffer)];
+	static Framebuffer *fboDefault = nullptr;
+	if (fboDefault == nullptr) {
+		fboDefault = reinterpret_cast<Framebuffer*>(fboDefaultData);
+		fboDefault->fbo = 0;
+		fboDefault->width = 1;
+		fboDefault->height = 1;
+		fboDefault->texColor = 0;
+		fboDefault->rboDepthStencil = 0;
+	}
+	return *fboDefault;
+}
+
+void Framebuffer::Clear(bool color, bool depth, bool stencil)
+{
+	Activate();
+	GLbitfield clearBits = 0;
+	if (color)
+		clearBits |= GL_COLOR_BUFFER_BIT;
+	if (depth)
+		clearBits |= GL_DEPTH_BUFFER_BIT;
+	if (stencil)
+		clearBits |= GL_STENCIL_BUFFER_BIT;
+	glClear(clearBits);
+}
-- 
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