From 5e34f7a8969f4afc169f034d34fb908019b3a389 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Mon, 14 Sep 2015 01:18:38 +0200
Subject: [PATCH] Reuse the VAO across all phases.

---
 effect_chain.cpp | 45 +++++++++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/effect_chain.cpp b/effect_chain.cpp
index 471d603..bf01716 100644
--- a/effect_chain.cpp
+++ b/effect_chain.cpp
@@ -1625,6 +1625,23 @@ void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height
 	glDepthMask(GL_FALSE);
 	check_error();
 
+	// Generate a VAO. All the phases should have exactly the same vertex attributes,
+	// so it's safe to reuse this.
+	float vertices[] = {
+		0.0f, 2.0f,
+		0.0f, 0.0f,
+		2.0f, 0.0f
+	};
+
+	GLuint vao;
+	glGenVertexArrays(1, &vao);
+	check_error();
+	glBindVertexArray(vao);
+	check_error();
+
+	GLuint position_vbo = fill_vertex_attribute(phases[0]->glsl_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
+	GLuint texcoord_vbo = fill_vertex_attribute(phases[0]->glsl_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices);  // Same as vertices.
+
 	set<Phase *> generated_mipmaps;
 
 	// We choose the simplest option of having one texture per output,
@@ -1666,6 +1683,12 @@ void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height
 	glUseProgram(0);
 	check_error();
 
+	cleanup_vertex_attribute(phases[0]->glsl_program_num, "position", position_vbo);
+	cleanup_vertex_attribute(phases[0]->glsl_program_num, "texcoord", texcoord_vbo);
+
+	glDeleteVertexArrays(1, &vao);
+	check_error();
+
 	if (do_phase_timing) {
 		// Get back the timer queries.
 		for (unsigned phase_num = 0; phase_num < phases.size(); ++phase_num) {
@@ -1779,28 +1802,9 @@ void EffectChain::execute_phase(Phase *phase, bool last_phase, map<Phase *, GLui
 	// from there.
 	setup_uniforms(phase);
 
-	// Now draw!
-	float vertices[] = {
-		0.0f, 2.0f,
-		0.0f, 0.0f,
-		2.0f, 0.0f
-	};
-
-	GLuint vao;
-	glGenVertexArrays(1, &vao);
-	check_error();
-	glBindVertexArray(vao);
-	check_error();
-
-	GLuint position_vbo = fill_vertex_attribute(glsl_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
-	GLuint texcoord_vbo = fill_vertex_attribute(glsl_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices);  // Same as vertices.
-
 	glDrawArrays(GL_TRIANGLES, 0, 3);
 	check_error();
 
-	cleanup_vertex_attribute(glsl_program_num, "position", position_vbo);
-	cleanup_vertex_attribute(glsl_program_num, "texcoord", texcoord_vbo);
-	
 	glUseProgram(0);
 	check_error();
 
@@ -1812,9 +1816,6 @@ void EffectChain::execute_phase(Phase *phase, bool last_phase, map<Phase *, GLui
 	if (!last_phase) {
 		resource_pool->release_fbo(fbo);
 	}
-
-	glDeleteVertexArrays(1, &vao);
-	check_error();
 }
 
 void EffectChain::setup_uniforms(Phase *phase)
-- 
2.39.2