From a0507d3ea62dac332659e0b1815d01fb2a2ead7f Mon Sep 17 00:00:00 2001
From: Phireh <Phireh@fukurokuju.dev>
Date: Sat, 4 Feb 2023 01:57:57 +0100
Subject: [PATCH] Basic hex gradient grid

---
 main.c              | 29 ++++++++++++++---------------
 shaders/vertex.glsl |  7 ++++++-
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/main.c b/main.c
index 84675c2..e1fd8fc 100644
--- a/main.c
+++ b/main.c
@@ -54,7 +54,7 @@ int main(void)
     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
 
-    window = glfwCreateWindow(800, 800, "Hello World", NULL, NULL);
+    window = glfwCreateWindow(800, 800, "Hello Hex", NULL, NULL);
     if (!window) return -1;
     glfwMakeContextCurrent(window);
     if (glewInit() != GLEW_OK) return -1;
@@ -112,16 +112,18 @@ int main(void)
     background_color.a = 1.0f;
 
     hexgrid_t grid;
-    grid.rows = 2;
-    grid.columns = 2;
+    grid.rows = 10;
+    grid.columns = 10;
     grid.hexes = calloc(1, sizeof(hex_t) * grid.rows * grid.columns);
 
+    // Scale of hexagon relative to screen. A 1:1 hexagon would reach the entire horizontal space
     float scale = 1.0f / 5.0f;
 
     for (size_t i = 0; i < grid.columns; ++i)
     {
         for (size_t j = 0; j < grid.rows; ++j)
         {
+            // Offset the X and Y coordinates of adjacent hexagons so they do not cut each other
             float offset = 0.0f;
             if (j % 2)
                 offset = sint(1.0f/6);
@@ -135,8 +137,6 @@ int main(void)
     }
 
     // Get OpenGL objects
-
-
     for (size_t i = 0; i < grid.rows * grid.columns; ++i)
     {
         hex_t *hex = &grid.hexes[i];
@@ -184,7 +184,6 @@ int main(void)
     //glBindBuffer(GL_ARRAY_BUFFER, 0);
     //glBindVertexArray(0);
 
-    int64_t framecount = 0;
     while (!glfwWindowShouldClose(window))
     {
         int width, height;
@@ -197,18 +196,20 @@ int main(void)
         glUseProgram(shader_program);
         //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 
-        // Set uniforms
-        vec4f hex_color;
-        hex_color.r = (float)(framecount % 1100)/1100;
-        hex_color.g = (float)(framecount % 300)/300;
-        hex_color.b = (float)(framecount % 1700)/1700;
-        hex_color.a = 1.0f;
 
-        set_uniform(shader_program, "uniform_color", hex_color);
 
         for (size_t i = 0; i < grid.rows * grid.columns; ++i)
         {
+
+            // Set uniforms
+            vec4f hex_color;
+            hex_color.r = (float)i / (grid.rows * grid.columns);
+            hex_color.g = (float)i / (grid.rows * grid.columns);
+            hex_color.b = (float)i / (grid.rows * grid.columns);
+            hex_color.a = 1.0f;
+            set_uniform(shader_program, "uniform_color", hex_color);
             glBindVertexArray(grid.hexes[i].vao);
+
             //log_debug("Binding VAO %d VBO %d EBO %d", grid.hexes[i].vao, grid.hexes[i].vbo, grid.hexes[i].ebo);
             glBindBuffer(GL_ARRAY_BUFFER, grid.hexes[i].vbo);
             glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, grid.hexes[i].ebo);
@@ -216,8 +217,6 @@ int main(void)
         }
         glfwPollEvents();
         glfwSwapBuffers(window);
-
-        ++framecount;
     }
     return 0;
 }
diff --git a/shaders/vertex.glsl b/shaders/vertex.glsl
index d85e06b..317caa1 100644
--- a/shaders/vertex.glsl
+++ b/shaders/vertex.glsl
@@ -2,8 +2,13 @@
 layout (location = 0) in vec3 pos;
 uniform vec4 uniform_color;
 out vec4 vertex_color;
+const mat4 to_draw_coordinates_matrix = mat4(
+    1., 0., 0., 0.,
+    0., 1., 0., 0.,
+    0., 0., 1., 0.,
+    -1, 1, 0, 1);
 void main()
 {
-    gl_Position = vec4(pos, 1.0f);
+    gl_Position = to_draw_coordinates_matrix*vec4(pos.x,-pos.y,pos.z, 1.0f);
     vertex_color = uniform_color;
 }