Enable Framebuffer Emulation on the Raspberry Pi

renderbuffer code was written by gonetz, not me

src/CMakeLists.txt

@@ -64,6 +64,7 @@ if(EXISTS "/opt/vc/include/bcm_host.h")
   set(GLES2 ON)
   add_definitions(
     -DVC
+    -DUSE_DEPTH_RENDERBUFFER
   )
   include_directories(
     "/opt/vc/include"

src/Config.cpp

@@ -43,11 +43,7 @@ void Config::resetToDefaults()
 	generalEmulation.polygonOffsetUnits = 0.0f;
 #endif
 
-#ifdef VC
-	frameBufferEmulation.enable = 0;
-#else
 	frameBufferEmulation.enable = 1;
-#endif
 	frameBufferEmulation.copyDepthToRDRAM = cdDisable;
 	frameBufferEmulation.copyFromRDRAM = 0;
 	frameBufferEmulation.copyAuxToRDRAM = 0;

src/DepthBuffer.cpp

@@ -19,6 +19,7 @@ const GLuint depthImageUnit = 2;
 
 DepthBuffer::DepthBuffer() : m_address(0), m_width(0), m_uly(0), m_lry(0),
 	m_depthImageFBO(0), m_pDepthImageTexture(nullptr), m_pDepthBufferTexture(nullptr),
+	m_depthRenderbuffer(0), m_depthRenderbufferWidth(0),
 	m_cleared(false), m_pResolveDepthBufferTexture(nullptr), m_resolved(false),
 	m_pDepthBufferCopyTexture(nullptr), m_copied(false)
 {
@@ -30,12 +31,14 @@ DepthBuffer::DepthBuffer() : m_address(0), m_width(0), m_uly(0), m_lry(0),
 DepthBuffer::DepthBuffer(DepthBuffer && _other) :
 	m_address(_other.m_address), m_width(_other.m_width), m_uly(_other.m_uly), m_lry(_other.m_lry),
 	m_depthImageFBO(_other.m_depthImageFBO), m_pDepthImageTexture(_other.m_pDepthImageTexture), m_pDepthBufferTexture(_other.m_pDepthBufferTexture),
+	m_depthRenderbuffer(_other.m_depthRenderbuffer), m_depthRenderbufferWidth(_other.m_depthRenderbufferWidth),
 	m_cleared(_other.m_cleared), m_pResolveDepthBufferTexture(_other.m_pResolveDepthBufferTexture), m_resolved(_other.m_resolved),
 	m_pDepthBufferCopyTexture(_other.m_pDepthBufferCopyTexture), m_copied(m_copied)
 {
 	_other.m_depthImageFBO = 0;
 	_other.m_pDepthImageTexture = nullptr;
 	_other.m_pDepthBufferTexture = nullptr;
+	_other.m_depthRenderbuffer = 0;
 	_other.m_pResolveDepthBufferTexture = nullptr;
 	_other.m_resolved = false;
 	_other.m_pDepthBufferCopyTexture = nullptr;
@@ -50,6 +53,8 @@ DepthBuffer::~DepthBuffer()
 		textureCache().removeFrameBufferTexture(m_pDepthImageTexture);
 	if (m_pDepthBufferTexture != nullptr)
 		textureCache().removeFrameBufferTexture(m_pDepthBufferTexture);
+	if (m_depthRenderbuffer != 0)
+		glDeleteRenderbuffers(1, &m_depthRenderbuffer);
 	if (m_pResolveDepthBufferTexture != nullptr)
 		textureCache().removeFrameBufferTexture(m_pResolveDepthBufferTexture);
 	if (m_copyFBO != 0)
@@ -157,24 +162,55 @@ void DepthBuffer::_initDepthBufferTexture(FrameBuffer * _pBuffer, CachedTexture
 	glBindTexture(GL_TEXTURE_2D, 0);
 }
 
+void DepthBuffer::_initDepthBufferRenderbuffer(FrameBuffer * _pBuffer)
+{
+	if (m_depthRenderbuffer != 0)
+		return;
+	u32 height;
+	if (_pBuffer != NULL) {
+		m_depthRenderbufferWidth = (u32)(_pBuffer->m_pTexture->width);
+		height = (u32)(_pBuffer->m_pTexture->height);
+	} else {
+		if (config.frameBufferEmulation.nativeResFactor == 0) {
+			m_depthRenderbufferWidth = video().getWidth();
+			height = video().getHeight();
+		} else {
+			m_depthRenderbufferWidth = VI.width * config.frameBufferEmulation.nativeResFactor;
+			height = VI.height * config.frameBufferEmulation.nativeResFactor;
+		}
+	}
+
+	glGenRenderbuffers(1, &m_depthRenderbuffer);
+	glBindRenderbuffer(GL_RENDERBUFFER, m_depthRenderbuffer);
+	glRenderbufferStorage(GL_RENDERBUFFER, fboFormats.depthInternalFormat, m_depthRenderbufferWidth, height);
+}
+
 void DepthBuffer::setDepthAttachment(GLenum _target)
 {
+#ifndef USE_DEPTH_RENDERBUFFER
 #ifdef GL_MULTISAMPLING_SUPPORT
 	if (config.video.multisampling != 0)
 		glFramebufferTexture2D(_target, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D_MULTISAMPLE, m_pDepthBufferTexture->glName, 0);
 	else
 #endif
 		glFramebufferTexture2D(_target, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, m_pDepthBufferTexture->glName, 0);
+#else
+	glFramebufferRenderbuffer(_target, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_depthRenderbuffer);
+#endif
 	m_copied = false;
 	m_resolved = false;
 }
 
 void DepthBuffer::initDepthBufferTexture(FrameBuffer * _pBuffer)
 {
+#ifndef USE_DEPTH_RENDERBUFFER
 	if (m_pDepthBufferTexture == nullptr) {
 		m_pDepthBufferTexture = textureCache().addFrameBufferTexture();
 		_initDepthBufferTexture(_pBuffer, m_pDepthBufferTexture, config.video.multisampling != 0);
 	}
+#else
+	_initDepthBufferRenderbuffer(_pBuffer);
+#endif
 
 #ifdef GL_MULTISAMPLING_SUPPORT
 	if (config.video.multisampling != 0 && m_pResolveDepthBufferTexture == nullptr) {

src/DepthBuffer.h

@@ -25,6 +25,8 @@ struct DepthBuffer
 	GLuint m_depthImageFBO;
 	CachedTexture *m_pDepthImageTexture;
 	CachedTexture *m_pDepthBufferTexture;
+	GLuint m_depthRenderbuffer;
+	u32 m_depthRenderbufferWidth;
 	bool m_cleared;
 	// multisampling
 	CachedTexture *m_pResolveDepthBufferTexture;
@@ -36,6 +38,7 @@ struct DepthBuffer
 
 private:
 	void _initDepthBufferTexture(FrameBuffer * _pBuffer, CachedTexture *_pTexture, bool _multisample);
+	void _initDepthBufferRenderbuffer(FrameBuffer * _pBuffer);
 	void _DepthBufferTexture(FrameBuffer * _pBuffer);
 };
 

src/FrameBuffer.cpp

@@ -707,16 +707,24 @@ void FrameBufferList::attachDepthBuffer()
 {
 	if (m_pCurrent == nullptr)
 		return;
+#ifdef VC
+	const GLenum discards[]  = {GL_DEPTH_ATTACHMENT};
+	glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards);
+#endif
 
 	DepthBuffer * pDepthBuffer = depthBufferList().getCurrent();
 	if (m_pCurrent->m_FBO > 0 && pDepthBuffer != nullptr) {
 		pDepthBuffer->initDepthImageTexture(m_pCurrent);
 		pDepthBuffer->initDepthBufferTexture(m_pCurrent);
+#ifndef USE_DEPTH_RENDERBUFFER
 #ifdef GLES2
 		if (pDepthBuffer->m_pDepthBufferTexture->realWidth == m_pCurrent->m_pTexture->realWidth) {
 #else
 		if (pDepthBuffer->m_pDepthBufferTexture->realWidth >= m_pCurrent->m_pTexture->realWidth) {
-#endif
+#endif // GLES2
+#else
+		if (pDepthBuffer->m_depthRenderbufferWidth == m_pCurrent->m_pTexture->realWidth) {
+#endif // USE_DEPTH_RENDERBUFFER
 			m_pCurrent->m_pDepthBuffer = pDepthBuffer;
 			pDepthBuffer->setDepthAttachment(GL_DRAW_FRAMEBUFFER);
 			if (video().getRender().isImageTexturesSupported() && config.frameBufferEmulation.N64DepthCompare != 0)

src/OpenGL.h

@@ -15,6 +15,7 @@
 #include <GLideN64_libretro.h>
 #elif GLES2
 #include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
 #define GL_DRAW_FRAMEBUFFER GL_FRAMEBUFFER
 #define GL_READ_FRAMEBUFFER GL_FRAMEBUFFER
 #define NO_BLIT_BUFFER_COPY