From 7e2b3da92839430cee7b63e6894f340cd31dda59 Mon Sep 17 00:00:00 2001
From: Gregory Hainaut <gregory.hainaut@gmail.com>
Date: Thu, 7 Jul 2016 21:33:59 +0200
Subject: [PATCH] gsdx ogl: monitor global GPU memory texture usage

So far there is a hardcoded limit at ~3.7GB

In the future, the limit will be reduced for low-end GPU.
---
 plugins/GSdx/GLState.cpp      |  6 ++++++
 plugins/GSdx/GLState.h        |  2 ++
 plugins/GSdx/GSTextureOGL.cpp | 26 ++++++++++++--------------
 plugins/GSdx/GSTextureOGL.h   |  4 +++-
 4 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/plugins/GSdx/GLState.cpp b/plugins/GSdx/GLState.cpp
index 39f7a7c6f1..88fbb80b35 100644
--- a/plugins/GSdx/GLState.cpp
+++ b/plugins/GSdx/GLState.cpp
@@ -57,6 +57,8 @@ namespace GLState {
 	GLuint program;
 	GLuint pipeline;
 
+	uint64 available_vram;
+
 	void Clear() {
 		fbo = 0;
 		viewport = GSVector2i(0, 0);
@@ -93,5 +95,9 @@ namespace GLState {
 		vs = 0;
 		program  = 0;
 		pipeline = 0;
+
+		// Set a max vram limit for texture allocation
+		// (256MB are reserved for PBO/IBO/VBO/UBO buffers)
+		available_vram = (4096u - 256u) * 1024u * 1024u;
 	}
 }
diff --git a/plugins/GSdx/GLState.h b/plugins/GSdx/GLState.h
index 5203526207..69e60c342d 100644
--- a/plugins/GSdx/GLState.h
+++ b/plugins/GSdx/GLState.h
@@ -59,5 +59,7 @@ namespace GLState {
 	extern GLuint program;
 	extern GLuint pipeline;
 
+	extern uint64 available_vram;
+
 	extern void Clear();
 }
diff --git a/plugins/GSdx/GSTextureOGL.cpp b/plugins/GSdx/GSTextureOGL.cpp
index b375e63d7b..43d59afb11 100644
--- a/plugins/GSdx/GSTextureOGL.cpp
+++ b/plugins/GSdx/GSTextureOGL.cpp
@@ -221,14 +221,14 @@ GSTextureOGL::GSTextureOGL(int type, int w, int h, int format, GLuint fbo_read)
 		case GL_DEPTH32F_STENCIL8:
 			m_int_format    = GL_DEPTH_STENCIL;
 			m_int_type      = GL_FLOAT_32_UNSIGNED_INT_24_8_REV;
-			m_int_shift     = 0;
+			m_int_shift     = 3; // 4 bytes for depth + 4 bytes for stencil by texels
 			break;
 
 			// Backbuffer
 		case 0:
 			m_int_format    = 0;
 			m_int_type      = 0;
-			m_int_shift     = 0;
+			m_int_shift     = 2; // 4 bytes by texels
 			break;
 
 		default:
@@ -238,6 +238,13 @@ GSTextureOGL::GSTextureOGL(int type, int w, int h, int format, GLuint fbo_read)
 			ASSERT(0);
 	}
 
+	m_mem_usage = (m_size.x * m_size.y) << m_int_shift;
+	if (m_mem_usage > GLState::available_vram) {
+		throw GSDXErrorOOM(); // Still time to do a prayer !
+	} else {
+		GLState::available_vram -= m_mem_usage;
+	}
+
 	// Generate & Allocate the buffer
 	switch (m_type) {
 		case GSTexture::Offscreen:
@@ -275,6 +282,8 @@ GSTextureOGL::~GSTextureOGL()
 
 	glDeleteTextures(1, &m_texture_id);
 
+	GLState::available_vram += m_mem_usage;
+
 	if (m_local_buffer)
 		_aligned_free(m_local_buffer);
 }
@@ -485,16 +494,5 @@ bool GSTextureOGL::Save(const string& fn, bool user_image, bool dds)
 
 uint32 GSTextureOGL::GetMemUsage()
 {
-	switch (m_type) {
-		case GSTexture::Offscreen:
-			return m_size.x * m_size.y * (4 + 4); // Texture + buffer
-		case GSTexture::Texture:
-		case GSTexture::RenderTarget:
-			return m_size.x * m_size.y * 4;
-		case GSTexture::DepthStencil:
-			return m_size.x * m_size.y * 8;
-		case GSTexture::Backbuffer:
-		default:
-			return 0;
-	}
+	return m_mem_usage;
 }
diff --git a/plugins/GSdx/GSTextureOGL.h b/plugins/GSdx/GSTextureOGL.h
index 298738a5c1..cba8601f64 100644
--- a/plugins/GSdx/GSTextureOGL.h
+++ b/plugins/GSdx/GSTextureOGL.h
@@ -53,12 +53,14 @@ class GSTextureOGL final : public GSTexture
 		int m_r_w;
 		int m_r_h;
 
-
 		// internal opengl format/type/alignment
 		GLenum m_int_format;
 		GLenum m_int_type;
 		uint32 m_int_shift;
 
+		// Allow to track size of allocated memory
+		uint32 m_mem_usage;
+
 	public:
 		explicit GSTextureOGL(int type, int w, int h, int format, GLuint fbo_read);
 		virtual ~GSTextureOGL();