From 6f3e688fa3f0bec5207bacf25541d1d7273a3611 Mon Sep 17 00:00:00 2001
From: blobt <klm777x7@gmail.com>
Date: Fri, 18 Sep 2020 10:54:46 +0800
Subject: [PATCH] =?UTF-8?q?framebuffer=20=E7=B1=BB=E5=B0=81=E8=A3=85?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 framebufferobject.cpp           | 79 +++++++++++++++++++++++++++++++++
 framebufferobject.h             | 17 +++++++
 renderFramework.vcxproj         |  2 +
 renderFramework.vcxproj.filters |  6 +++
 4 files changed, 104 insertions(+)
 create mode 100644 framebufferobject.cpp
 create mode 100644 framebufferobject.h

diff --git a/framebufferobject.cpp b/framebufferobject.cpp
new file mode 100644
index 0000000..1cd6019
--- /dev/null
+++ b/framebufferobject.cpp
@@ -0,0 +1,79 @@
+#include "framebufferobject.h"
+
+FrameBufferObject::FrameBufferObject()
+{
+	glGenFramebuffers(1, &mFrameBufferObject);
+}
+
+void FrameBufferObject::AttachColorBuffer(const char * bufferName, GLenum attachment, int width, int height)
+{
+	GLuint colorBuffer;
+	glBindFramebuffer(GL_FRAMEBUFFER, mFrameBufferObject);
+	glGenTextures(1, &colorBuffer);
+	glBindTexture(GL_TEXTURE_2D, colorBuffer);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+	glBindTexture(GL_TEXTURE_2D, 0);
+	glFramebufferTexture2D(GL_FRAMEBUFFER, attachment, GL_TEXTURE_2D, colorBuffer, 0);
+	mDrawBuffers.push_back(attachment);
+	mBuffers.insert(std::pair<std::string, GLuint>(bufferName, colorBuffer));
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+}
+
+void FrameBufferObject::AttachDepthBuffer(const char * bufferName, int width, int height)
+{
+	GLuint depthMap;
+	glBindFramebuffer(GL_FRAMEBUFFER, mFrameBufferObject);
+	glGenTextures(1, &depthMap);
+	glBindTexture(GL_TEXTURE_2D, depthMap);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, width, height, 0, GL_DEPTH_COMPONENT, depthMap, 0);
+	glBindTexture(GL_TEXTURE_2D, 0);
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthMap, 0);
+	mBuffers.insert(std::pair<std::string, GLuint>(bufferName, depthMap));
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+}
+
+void FrameBufferObject::Finish()
+{
+	int nCount = (int)mDrawBuffers.size();
+	if (nCount > 0) {
+		GLenum *buffers = new GLenum[nCount];
+		int i = 0;
+		while (i < nCount) {
+			buffers[i] = mDrawBuffers[i];
+			i++;
+		}
+		glBindFramebuffer(GL_FRAMEBUFFER, mFrameBufferObject);
+		glDrawBuffers(nCount, buffers);
+		glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	}
+}
+
+void FrameBufferObject::Bind()
+{
+	glGetIntegerv(GL_FRAMEBUFFER_BINDING, &mPrevFrameBuffer);
+	glBindFramebuffer(GL_FRAMEBUFFER, mFrameBufferObject);
+	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+}
+
+void FrameBufferObject::Unbind()
+{
+	glBindFramebuffer(GL_FRAMEBUFFER, mPrevFrameBuffer);
+}
+
+GLuint FrameBufferObject::GetBuffer(const char * bufferName)
+{
+	auto iter = mBuffers.find(bufferName);
+	if (iter != mBuffers.end()) {
+		return iter->second;
+	}
+	return 0;
+}
+
+
diff --git a/framebufferobject.h b/framebufferobject.h
new file mode 100644
index 0000000..5c79e80
--- /dev/null
+++ b/framebufferobject.h
@@ -0,0 +1,17 @@
+#pragma once
+#include "ggl.h"
+class FrameBufferObject {
+public:
+	GLuint mFrameBufferObject;
+	GLint mPrevFrameBuffer;
+	std::map<std::string, GLuint> mBuffers;
+	std::vector<GLenum> mDrawBuffers;
+public:
+	FrameBufferObject();
+	void AttachColorBuffer(const char* bufferName, GLenum attachment, int width, int height);
+	void AttachDepthBuffer(const char* bufferName, int width, int height);
+	void Finish();
+	void Bind();
+	void Unbind();
+	GLuint GetBuffer(const char* bufferName);
+};
\ No newline at end of file
diff --git a/renderFramework.vcxproj b/renderFramework.vcxproj
index fd9d02f..75fe671 100644
--- a/renderFramework.vcxproj
+++ b/renderFramework.vcxproj
@@ -126,6 +126,7 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="framebufferobject.cpp" />
     <ClCompile Include="main.cpp" />
     <ClCompile Include="model.cpp" />
     <ClCompile Include="scene.cpp" />
@@ -134,6 +135,7 @@
     <ClCompile Include="vertexbuffer.cpp" />
   </ItemGroup>
   <ItemGroup>
+    <ClInclude Include="framebufferobject.h" />
     <ClInclude Include="ggl.h" />
     <ClInclude Include="model.h" />
     <ClInclude Include="scene.h" />
diff --git a/renderFramework.vcxproj.filters b/renderFramework.vcxproj.filters
index 9a0550a..4bbf003 100644
--- a/renderFramework.vcxproj.filters
+++ b/renderFramework.vcxproj.filters
@@ -33,6 +33,9 @@
     <ClCompile Include="model.cpp">
       <Filter>源文件</Filter>
     </ClCompile>
+    <ClCompile Include="framebufferobject.cpp">
+      <Filter>源文件</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="ggl.h">
@@ -53,5 +56,8 @@
     <ClInclude Include="model.h">
       <Filter>源文件</Filter>
     </ClInclude>
+    <ClInclude Include="framebufferobject.h">
+      <Filter>源文件</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file