a-game

commit 3418f76c8a1741b85df476212d4375f860c9c9bc
parent 4076e7945b53cf1f776a72dda0801475a0eeb445
Author: amin <dev@aminmesbah.com>
Date:   Thu, 25 Apr 2019 22:52:59 +0000

Make the debug quads look nicer

FossilOrigin-Name: f9765db60ad8d5f8cbd6fce6f333841879f846f498958324db5b338c75096c75
Diffstat:
M
src/game.c
 | 
33
++++++++++++++++++++++++++-------
M
src/game.h
 | 
1
+

2 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/src/game.c b/src/game.c
@@ -25,28 +25,31 @@ internal void game_init(struct GameMemory *game_memory, v2u framebuffer)
 
     // set up and load tiles
     {
-        GLfloat square_vertices[] = {
+        GLfloat quad_vertices[] = {
              0.5f,  0.5f,
              0.5f, -0.5f,
             -0.5f, -0.5f,
             -0.5f,  0.5f,
         };
 
-        GLuint square_elements[] = { 0, 1, 3, 1, 2, 3 };
+        GLuint quad_elements[] = { 0, 1, 3, 1, 2, 3 };
+        GLuint rect_elements[] = { 0, 1, 1, 2, 2, 3, 3, 0 };
 
         GLuint vao;
         GLuint quad_vbo;
         GLuint quad_ebo;
+        GLuint rect_ebo;
         glGenVertexArrays(1, &vao);
         glGenBuffers(1, &quad_vbo);
         glGenBuffers(1, &quad_ebo);
+        glGenBuffers(1, &rect_ebo);
 
         // NOTE(amin): We will leave this bound for the duration of the game.
         // There should not be any calls to glBindVertexArray(0).
         glBindVertexArray(vao);
 
         glBindBuffer(GL_ARRAY_BUFFER, quad_vbo);
-        glBufferData(GL_ARRAY_BUFFER, sizeof(square_vertices), square_vertices, GL_STATIC_DRAW);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(quad_vertices), quad_vertices, GL_STATIC_DRAW);
         glVertexAttribPointer(
             0,                   // Data location
             2,                   // Number of values
@@ -58,11 +61,17 @@ internal void game_init(struct GameMemory *game_memory, v2u framebuffer)
 
         glEnableVertexAttribArray(0);
         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_ebo);
-        glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(square_elements), square_elements, GL_STATIC_DRAW);
+        glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(quad_elements), quad_elements, GL_STATIC_DRAW);
+
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, rect_ebo);
+        glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(rect_elements), rect_elements, GL_STATIC_DRAW);
+
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_ebo);
 
         game_state->renderer.vao = vao;
         game_state->renderer.quad_vbo = quad_vbo;
         game_state->renderer.quad_ebo = quad_ebo;
+        game_state->renderer.rect_ebo = rect_ebo;
     }
 
     {
@@ -441,10 +450,8 @@ void game_update_and_render(struct GameMemory *game_memory, struct GameInput *ga
                 .min = {glmth_min(player->pos.x, new_p.x), glmth_min(player->pos.y, new_p.y)},
                 .max = {glmth_max(player->pos.x, new_p.x), glmth_max(player->pos.y, new_p.y)},
             };
-            //RENDER_COLLISION_DEBUG_QUAD(player_traversal_bb, ((v3) {0.4f, 0.4f, 0.4f}));
 
             rect player_traversal_occupancy_bb = glmth_minkowski_sum_rect_rect(player_traversal_bb, player->dimensions);
-            //RENDER_COLLISION_DEBUG_QUAD(player_traversal_occupancy_bb, ((v3) {0.8f, 0.4f, 0.8f}));
 
             rect tile_search_range = {
                 .min = {
@@ -633,10 +640,20 @@ internal void game_cleanup(struct GameMemory *game_memory)
     glDeleteVertexArrays(1, &game_state->renderer.vao);
     glDeleteBuffers(1, &game_state->renderer.quad_vbo);
     glDeleteBuffers(1, &game_state->renderer.quad_ebo);
+    glDeleteBuffers(1, &game_state->renderer.rect_ebo);
 }
 
 internal void render_debug_quad(struct GameState *game_state, rect r, v3 color, m4 *view, m4 *projection)
 {
+    GLint initial_ebo = 0;
+    // TODO: Remove this potentially expensive call and just track the current
+    // EBO manually.
+    glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &initial_ebo);
+    // NOTE(amin): If the GLint we get is less than zero, it will underflow
+    // when it gets converted to a GLuint as an argument to glBindBuffer.
+    assert(initial_ebo >= 0);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, game_state->renderer.rect_ebo);
     glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
     shader_use(&game_state->renderer.shader);
 
@@ -652,6 +669,8 @@ internal void render_debug_quad(struct GameState *game_state, rect r, v3 color, 
     shader_setm4(&game_state->renderer.shader, "view", view);
     shader_setm4(&game_state->renderer.shader, "projection", projection);
 
-    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+    glDrawElements(GL_LINES, 8, GL_UNSIGNED_INT, 0);
     glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, initial_ebo);
 }
diff --git a/src/game.h b/src/game.h
@@ -21,6 +21,7 @@ struct RendererState
     GLuint vao;
     GLuint quad_vbo;
     GLuint quad_ebo;
+    GLuint rect_ebo;
     struct Shader shader;
 };