From 1f593b96acd57df4508dcc7a22d1f91f0b7bcd37 Mon Sep 17 00:00:00 2001
From: Abdelrahman <said.abdelrahman89@gmail.com>
Date: Sun, 22 Sep 2024 16:24:29 +0100
Subject: [PATCH] Setup projection matrix and position the quad properly
---
shaders/vert.glsl | 3 ++-
src/main.cc | 39 +++++++++++++++++++++++++++++----------
2 files changed, 31 insertions(+), 11 deletions(-)
diff --git a/shaders/vert.glsl b/shaders/vert.glsl
index 2c9821a..8ce7bc9 100644
--- a/shaders/vert.glsl
+++ b/shaders/vert.glsl
@@ -4,10 +4,11 @@ layout(location=0) in vec3 position;
layout(location=1) in vec3 vert_colour;
uniform mat4 u_model;
+uniform mat4 u_projection;
out vec3 vert_colours;
void main() {
vert_colours = vert_colour;
- gl_Position = u_model * vec4(position, 1.0f);
+ gl_Position = u_projection * u_model * vec4(position, 1.0f);
};
diff --git a/src/main.cc b/src/main.cc
index b7d6a3b..aa14b70 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -1,5 +1,6 @@
#include "glad/glad.h"
#include "glm/gtc/type_ptr.hpp"
+#include "glm/trigonometric.hpp"
#include <SDL2/SDL.h>
#include <SDL2/SDL_error.h>
#include <SDL2/SDL_video.h>
@@ -52,6 +53,10 @@ struct App {
glm::mat4 model_mat;
GLint u_model_idx;
+ // Projection matrix to be sent as uniform to the vertex shader
+ glm::mat4 projection_mat;
+ GLint u_projection_idx;
+
bool running;
};
@@ -123,8 +128,13 @@ int init(App &app) {
glGetString(GL_SHADING_LANGUAGE_VERSION)
);
- app.speed = 0.02f;
- app.model_mat = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f));
+ app.speed = 0.02f;
+ app.model_mat = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f));
+ app.projection_mat = glm::perspective(glm::radians(60.0f),
+ (float)WINDOW_WIDTH / (float)WINDOW_HEIGHT,
+ 0.1f,
+ 20.0f
+ );
return EXIT_CODE_SUCCESS;
}
@@ -132,17 +142,17 @@ int init(App &app) {
void create_vertex_spec(App &app) {
const std::vector<GLfloat> vertices = {
// vert0
- -0.5f, -0.5f, 0.0f, // position
- 1.0f, 0.0f, 0.0f, // colour
+ -0.5f, -0.5f, -1.5f, // position
+ 1.0f, 0.0f, 0.0f, // colour
// vert1
- 0.5f, -0.5f, 0.0f, // position
- 0.0f, 1.0f, 0.0f, // colour
+ 0.5f, -0.5f, -1.5f, // position
+ 0.0f, 1.0f, 0.0f, // colour
// vert2
- -0.5f, 0.5f, 0.0f, // position
- 0.0f, 0.0f, 1.0f, // colour
+ -0.5f, 0.5f, -1.5f, // position
+ 0.0f, 0.0f, 1.0f, // colour
// vert3
- 0.5f, 0.5f, 0.0f, // position
- 1.0f, 1.0f, 0.0f, // colour
+ 0.5f, 0.5f, -1.5f, // position
+ 1.0f, 1.0f, 0.0f, // colour
};
const std::vector<GLuint> indices = {
@@ -210,6 +220,12 @@ void create_graphics_pipeline(App &app) {
if (app.u_model_idx < 0) {
printf("Failed to find uniform %s\n", u_model);
}
+
+ const char *u_projection = "u_projection";
+ app.u_projection_idx = glGetUniformLocation(app.shader_program, u_projection);
+ if (app.u_projection_idx < 0) {
+ printf("Failed to find uniform %s\n", u_projection);
+ }
}
void run_main_loop(App &app) {
@@ -242,6 +258,9 @@ void run_main_loop(App &app) {
if (app.u_model_idx >= 0) {
glUniformMatrix4fv(app.u_model_idx, 1, GL_FALSE, glm::value_ptr(app.model_mat));
}
+ if (app.u_projection_idx >= 0) {
+ glUniformMatrix4fv(app.u_projection_idx, 1, GL_FALSE, glm::value_ptr(app.projection_mat));
+ }
// End pre draw setup
// Draw call