From d5429ad5af32b8eb420cd4809f0fdd59827d50c2 Mon Sep 17 00:00:00 2001
From: 0xdeadbeer <64986162+0xdeadbeer@users.noreply.github.com>
Date: Sat, 14 Oct 2023 18:24:51 +0200
Subject: [PATCH] Main: add simple perspective rendering

---
 .gitignore     |  2 ++
 CMakeLists.txt |  6 +++--
 main.c         | 71 ++++++++++++++++++++++++++++++++++++--------------
 shader.frag    |  4 +--
 shader.vert    |  6 ++++-
 5 files changed, 65 insertions(+), 24 deletions(-)

diff --git a/.gitignore b/.gitignore
index 990936c..24dd928 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 .idea/
 cmake-build-debug/
+build/
+.ccls-cache/
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9ed9e10..db509af 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,11 +13,13 @@ add_executable(${PROJECT_NAME} ${HEADER_FILES} ${SOURCE_FILES} ${SHADER_FILES})
 # We need a CMAKE_DIR with some code to find external dependencies
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/")
 
+find_package(PkgConfig REQUIRED)
 find_package(OpenGL REQUIRED)
 find_package(GLUT REQUIRED)
 find_package(GLEW REQUIRED)
 find_package(assimp REQUIRED)
+find_package(cglm REQUIRED)
 
-include_directories(${PROJECT_NAME} ${OPENGL_INCLUDE_DIRS} ${GLUT_INCLUDE_DIRS} ${GLEW_INCLUDE_DIRS} ${ASSIMP_INCLUDE_DIRS})
+include_directories(${PROJECT_NAME} ${OPENGL_INCLUDE_DIRS} ${GLUT_INCLUDE_DIRS} ${GLEW_INCLUDE_DIRS} ${ASSIMP_INCLUDE_DIRS} ${CGLM_INCLUDE_DIRS})
 
-target_link_libraries(${PROJECT_NAME} ${OPENGL_LIBRARIES} ${GLUT_LIBRARIES} ${GLEW_LIBRARIES} ${ASSIMP_LIBRARIES})
\ No newline at end of file
+target_link_libraries(${PROJECT_NAME} ${OPENGL_LIBRARIES} ${GLUT_LIBRARIES} ${GLEW_LIBRARIES} ${ASSIMP_LIBRARIES} ${CGLM_LIBRARIES} m)
\ No newline at end of file
diff --git a/main.c b/main.c
index 1ca0630..1a0653f 100644
--- a/main.c
+++ b/main.c
@@ -1,9 +1,8 @@
 #include <stdio.h>
 #include <GL/glew.h>
 #include <GL/freeglut.h>
-#include <pthread.h>
-#include <sys/inotify.h>
 #include <unistd.h>
+#include <cglm/cglm.h>
 
 unsigned int vao;
 unsigned int vbo;
@@ -73,18 +72,6 @@ int load_shader(const char *path, unsigned int shader) {
     return 0;
 }
 
-void display() {
-    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
-    glClear(GL_COLOR_BUFFER_BIT);
-
-    glUseProgram(shader_program);
-    glBindVertexArray(vao);
-
-    glDrawArrays(GL_TRIANGLES, 0, 3);
-
-    glutSwapBuffers();
-}
-
 int load_shaders() {
     glDeleteProgram(shader_program);
     shader_program = glCreateProgram();
@@ -122,11 +109,57 @@ int load_shaders() {
     glDeleteShader(vertex_shader);
     glDeleteShader(fragment_shader);
 
-    display();
-
     return 0;
 }
 
+float degs = 0;
+
+void display() {
+    mat4 model;
+    vec3 model_axis = {0.5f, 0.5f, 0.5f};
+    mat4 view;
+    vec3 view_translate = {0.0f, 0.0f, -3.0f};
+    mat4 projection;
+    GLint viewport[4]; // viewport: x, y, width, height
+
+    GLint model_uniform;
+    GLint view_uniform;
+    GLint projection_uniform;
+
+    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    glGetIntegerv(GL_VIEWPORT, viewport);
+
+    glm_mat4_identity(model);
+
+    glm_rotate(model, glm_rad((float) degs ), model_axis);
+    degs += 0.01f;
+
+    model_uniform = glGetUniformLocation(shader_program, "model");
+    glUniformMatrix4fv(model_uniform, 1, GL_FALSE, (float *) model);
+
+    glm_mat4_identity(view);
+    glm_translate(view, view_translate);
+
+    view_uniform = glGetUniformLocation(shader_program, "view");
+    glUniformMatrix4fv(view_uniform, 1, GL_FALSE, (float *) view);
+
+    glm_mat4_identity(projection);
+    glm_perspective(glm_rad(45.0f), (float)viewport[2]/(float)viewport[3], 0.01f, 100.0f, projection);
+
+    projection_uniform = glGetUniformLocation(shader_program, "projection");
+    glUniformMatrix4fv(projection_uniform, 1, GL_FALSE, (float *) projection);
+
+    glUseProgram(shader_program);
+    glBindVertexArray(vao);
+
+    glDrawArrays(GL_TRIANGLES, 0, 3);
+
+    glutSwapBuffers();
+    glutPostRedisplay();
+}
+
 void keyboard(unsigned char key, int x, int y) {
     switch (key) {
         case '\x1B':
@@ -137,11 +170,11 @@ void keyboard(unsigned char key, int x, int y) {
         case 'r':
         case 'R':
             if (load_shaders() != 0) {
-                fprintf(stderr, "Error: reloading shaders");
-                break;
+                fprintf(stderr, "Error: reloading shaders\n");
+                exit(EXIT_FAILURE);
             }
 
-            fprintf(stdout, "Status: successfully reloaded shaders");
+            fprintf(stdout, "Status: successfully reloaded shaders\n");
 
             break;
         default:
diff --git a/shader.frag b/shader.frag
index 38e8927..1faf9a6 100644
--- a/shader.frag
+++ b/shader.frag
@@ -3,6 +3,6 @@ in vec3 color;
 out vec4 output;
 
 void main() {
-//    output = vec4(color.xyz, 1.0f);
-    output = vec4(1.0, 1.0, 1.0, 1.0);
+    output = vec4(color.xyz, 1.0f);
+//    output = vec4(1.0, 1.0, 1.0, 1.0);
 }
\ No newline at end of file
diff --git a/shader.vert b/shader.vert
index 7c49743..78d38d6 100644
--- a/shader.vert
+++ b/shader.vert
@@ -2,9 +2,13 @@
 layout (location = 0) in vec3 pos;
 layout (location = 1) in vec3 col;
 
+uniform mat4 model;
+uniform mat4 view;
+uniform mat4 projection;
+
 out vec3 color;
 
 void main() {
-    gl_Position = vec4(pos.x, pos.y, pos.z, 1.0f);
+    gl_Position = projection * view * model * vec4(pos.xyz, 1.0);
     color = col;
 }
\ No newline at end of file