Optimization #1: use TRIANGLE_STRIP instead of TRIANGLES

Author: sdavydouski

src/graphics/ParticleEmitter.cpp

@@ -8,13 +8,10 @@ ParticleEmitter::ParticleEmitter(ShaderProgram *shaderProgram,
                                  GLuint amount)
     : shaderProgram_(shaderProgram), texture_(texture), amount_(amount), lastUsedParticle_(0) {
     GLfloat quad[] = {
-        0.0f, 1.0f, 0.0f, 1.0f,
-        1.0f, 0.0f, 1.0f, 0.0f,
         0.0f, 0.0f, 0.0f, 0.0f,
-
         0.0f, 1.0f, 0.0f, 1.0f,
-        1.0f, 1.0f, 1.0f, 1.0f,
-        1.0f, 0.0f, 1.0f, 0.0f
+        1.0f, 0.0f, 1.0f, 0.0f,
+        1.0f, 1.0f, 1.0f, 1.0f
     };
 
     glGenVertexArrays(1, &VAO_);
@@ -73,7 +70,7 @@ void ParticleEmitter::render(float scale) {
             shaderProgram_->setUniform("particleColor", particle.color);
             texture_->bind();
             glBindVertexArray(VAO_);
-            glDrawArrays(GL_TRIANGLES, 0, 6);
+            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
             glBindVertexArray(0);
         }
     }

src/graphics/PostProcessor.cpp

@@ -48,7 +48,7 @@ void PostProcessor::render(GLfloat time, GLfloat scale) {
     glActiveTexture(GL_TEXTURE0);
     glBindTexture(GL_TEXTURE_2D, textureId_);
     glBindVertexArray(VAO_);
-    glDrawArrays(GL_TRIANGLES, 0, 6);
+    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     glBindVertexArray(0);
 }
 
@@ -107,13 +107,10 @@ void PostProcessor::initTexture() {
 
 void PostProcessor::initVAO() {
     GLfloat quad[] = {
-        -1.0f, -1.0f, 0.0f, 0.0f,
-        1.0f,  1.0f, 1.0f, 1.0f,
-        -1.0f,  1.0f, 0.0f, 1.0f,
-
         -1.0f, -1.0f, 0.0f, 0.0f,
         1.0f, -1.0f, 1.0f, 0.0f,
-        1.0f,  1.0f, 1.0f, 1.0f
+        -1.0f,  1.0f, 0.0f, 1.0f,
+        1.0f,  1.0f, 1.0f, 1.0f,
     };
 
     glGenVertexArrays(1, &VAO_);

src/graphics/SpriteRenderer.cpp

@@ -14,13 +14,10 @@ void SpriteRenderer::init(ShaderProgram* shaderProgram) {
 
     GLfloat vertices[] = {
         // Pos      // Tex
-        0.0f, 1.0f, 0.0f, 1.0f,
-        1.0f, 0.0f, 1.0f, 0.0f,
         0.0f, 0.0f, 0.0f, 0.0f,
-
         0.0f, 1.0f, 0.0f, 1.0f,
-        1.0f, 1.0f, 1.0f, 1.0f,
-        1.0f, 0.0f, 1.0f, 0.0f
+        1.0f, 0.0f, 1.0f, 0.0f,
+        1.0f, 1.0f, 1.0f, 1.0f
     };
 
     glGenVertexArrays(1, &VAO_);
@@ -57,7 +54,7 @@ void SpriteRenderer::renderSprite(const Texture* texture,
     texture->bind();
 
     glBindVertexArray(VAO_);
-    glDrawArrays(GL_TRIANGLES, 0, 6);
+    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     glBindVertexArray(0);
 
     shaderProgram_->end();

src/graphics/TextRenderer.cpp

@@ -44,13 +44,10 @@ void TextRenderer::renderText(const std::string& text, const glm::vec2& position
         auto yPosition = position.y;
 
         GLfloat vertices[] = {
-            xPosition,         yPosition,          glyph.uvs[0].x, glyph.uvs[0].y,
-            xPosition + width, yPosition - height, glyph.uvs[1].x, glyph.uvs[1].y,
             xPosition,         yPosition - height, glyph.uvs[0].x, glyph.uvs[1].y,
-
             xPosition,         yPosition,          glyph.uvs[0].x, glyph.uvs[0].y,
-            xPosition + width, yPosition,          glyph.uvs[1].x, glyph.uvs[0].y,
             xPosition + width, yPosition - height, glyph.uvs[1].x, glyph.uvs[1].y,
+            xPosition + width, yPosition,          glyph.uvs[1].x, glyph.uvs[0].y
         };
 
         glBufferSubData(GL_ARRAY_BUFFER, sizeof(vertices) * i, sizeof(vertices), vertices);
@@ -60,7 +57,7 @@ void TextRenderer::renderText(const std::string& text, const glm::vec2& position
     }
 
     // Render quads
-    glDrawArrays(GL_TRIANGLES, 0, 6 * text.length());
+    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4 * text.length());
 
     glBindBuffer(GL_ARRAY_BUFFER, 0);
     glBindVertexArray(0);

src/main.cpp

@@ -3,13 +3,13 @@
 #include <GLFW/glfw3.h>
 #include "Game.h"
 
-//const int width = 800;
-//const int height = 600;
-//bool isFullScreen = false;
+const int width = 800;
+const int height = 600;
+bool isFullScreen = false;
 
-const int width = 1920;
-const int height = 1080;
-bool isFullScreen = true;
+//const int width = 1920;
+//const int height = 1080;
+//bool isFullScreen = true;
 
 int main(int argc, char* argv[]) {
     Game breakout(width, height, isFullScreen);