From 20c37d8d0e48b23681d78ebc866f05bc09d4fbc3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Thu, 10 Jan 2013 10:14:39 +0100
Subject: [PATCH] Use VBO to draw UI, just because that's how it's supposed to
 be done.

---
 gfx_es2/draw_buffer.cpp | 36 ++++++++++++++++++++++++++++++------
 gfx_es2/draw_buffer.h   | 16 +++++++++++-----
 2 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/gfx_es2/draw_buffer.cpp b/gfx_es2/draw_buffer.cpp
index bd8f803551..c7d6b5258b 100644
--- a/gfx_es2/draw_buffer.cpp
+++ b/gfx_es2/draw_buffer.cpp
@@ -21,12 +21,34 @@ DrawBuffer::DrawBuffer() : count_(0), atlas(0) {
 	verts_ = new Vertex[MAX_VERTS];
 	fontscalex = 1.0f;
 	fontscaley = 1.0f;
+	inited_ = false;
+	register_gl_resource_holder(this);
 }
 DrawBuffer::~DrawBuffer() {
+	unregister_gl_resource_holder(this);
 	delete [] verts_;
 }
 
+void DrawBuffer::Init() {
+	if (inited_)
+		return;
+	inited_ = true;
+	glGenBuffers(1, (GLuint *)&vbo_);
+}
+
+void DrawBuffer::Shutdown() {
+	glDeleteBuffers(1, (GLuint *)&vbo_);
+	vbo_ = 0;
+	inited_ = false;
+}
+
+void DrawBuffer::GLLost() {
+	inited_ = false;
+	Init();
+}
+
 void DrawBuffer::Begin(DrawBufferMode dbmode) {
+	Init();
 	count_ = 0;
 	mode_ = dbmode;
 }
@@ -38,11 +60,12 @@ void DrawBuffer::End() {
 void DrawBuffer::Flush(const GLSLProgram *program, bool set_blend_state) {
 	if (count_ == 0)
 		return;
-	glBindBuffer(GL_ARRAY_BUFFER, 0);
+	glBindBuffer(GL_ARRAY_BUFFER, vbo_);
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * count_, verts_, GL_STREAM_DRAW);
 	if (set_blend_state) {
-	glstate.blend.enable();
-	glstate.blendFunc.set(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+		glstate.blend.enable();
+		glstate.blendFunc.set(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 	}
 	glUniform1i(program->sampler0, 0);
 	glEnableVertexAttribArray(program->a_position);
@@ -50,10 +73,10 @@ void DrawBuffer::Flush(const GLSLProgram *program, bool set_blend_state) {
 	if (program->a_texcoord0 != -1)
 		glEnableVertexAttribArray(program->a_texcoord0);
 	GL_CHECK();
-	glVertexAttribPointer(program->a_position, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), &verts_[0].x);
-	glVertexAttribPointer(program->a_color, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(Vertex), &verts_[0].rgba);
+	glVertexAttribPointer(program->a_position, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, x));
+	glVertexAttribPointer(program->a_color, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(Vertex), (void *)offsetof(Vertex, rgba));
 	if (program->a_texcoord0 != -1)
-		glVertexAttribPointer(program->a_texcoord0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), &verts_[0].u);
+		glVertexAttribPointer(program->a_texcoord0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, u));
 	glDrawArrays(mode_ == DBMODE_LINES ? GL_LINES : GL_TRIANGLES, 0, count_);
 	GL_CHECK();
 	glDisableVertexAttribArray(program->a_position);
@@ -61,6 +84,7 @@ void DrawBuffer::Flush(const GLSLProgram *program, bool set_blend_state) {
 	if (program->a_texcoord0 != -1)
 		glDisableVertexAttribArray(program->a_texcoord0);
 	GL_CHECK();
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
 
 	count_ = 0;
 }
diff --git a/gfx_es2/draw_buffer.h b/gfx_es2/draw_buffer.h
index 3e202238cb..1ec42a847f 100644
--- a/gfx_es2/draw_buffer.h
+++ b/gfx_es2/draw_buffer.h
@@ -5,6 +5,7 @@
 #include "base/basictypes.h"
 #include "base/color.h"
 #include "base/display.h"
+#include "gfx/gl_lost_manager.h"
 
 struct Atlas;
 
@@ -36,13 +37,12 @@ enum DrawBufferMode {
 	DBMODE_LINES = 1
 };
 
-struct GradientStop 
-{
+struct GradientStop {
 	float t;
 	uint32_t color;
 };
 
-class DrawBuffer {
+class DrawBuffer : public GfxResourceHolder {
 public:
 	DrawBuffer();
 	~DrawBuffer();
@@ -50,10 +50,15 @@ public:
 	void Begin(DrawBufferMode mode = DBMODE_NORMAL);
 	void End();
 
+	// TODO: Enforce these. Now Init is autocalled and shutdown not called.
+	void Init();
+	void Shutdown();
+	virtual void GLLost();
+
 	int Count() const { return count_; }
 
 	void Flush(const GLSLProgram *program, bool set_blend_state=true);
-	
+
 	void Rect(float x, float y, float w, float h, uint32 color, int align = ALIGN_TOPLEFT);
 	void hLine(float x1, float y, float x2, uint32 color) { Rect(x1, y, x2 - x1, pixel_in_dps, color); }
 	void vLine(float x, float y1, float y2, uint32 color) { Rect(x, y1, pixel_in_dps, y2 - y1, color); }
@@ -121,7 +126,6 @@ public:
 	void SetClipRect(float x1, float y1, float x2, float y2);
 	void NoClip();
 
-
 private:
 	void DoAlign(int flags, float *x, float *y, float *w, float *h);
 	struct Vertex {
@@ -130,11 +134,13 @@ private:
 		float u, v;
 	};
 
+	int vbo_;
 	Vertex *verts_;
 	int count_;
 	DrawBufferMode mode_;
 	const Atlas *atlas;
 
+	bool inited_;
 	float fontscalex;
 	float fontscaley;
 };