117 lines
4.1 KiB
C
117 lines
4.1 KiB
C
#include <GL/glew.h>
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#include "SDL3/SDL_surface.h"
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#include "SDL3_image/SDL_image.h"
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#include "arena_allocator.h"
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#include "mesh.h"
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wn_mesh *wn_mesh_init(Arena *arena, wn_shader *shader) {
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// set up vertex data (and buffer(s)) and configure vertex attributes
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wn_mesh *mesh = (wn_mesh *)arena_init(arena, sizeof(wn_mesh));
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arena_deinit_task_push(arena, (ArenaDeinitTask){.func_ptr = *wn_mesh_deinit,
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.func_param = mesh,
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.next = NULL});
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mesh->shader = shader;
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float vertices[] = {
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0.5f, 0.5f, 0.0f, 1.0f, 1.0f, // top right
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0.5f, -0.5f, 0.0f, 1.0f, 0.0f, // bottom right
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-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, // bottom left
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-0.5f, 0.5f, 0.0f, 0.0f, 1.0f // top left
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};
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unsigned int indices[] = {
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0, 1, 3, // first Triangle
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1, 2, 3 // second Triangle
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};
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glGenVertexArrays(1, &mesh->VAO);
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glGenBuffers(1, &mesh->VBO);
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glGenBuffers(1, &mesh->EBO);
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// bind the Vertex Array Object first, then bind and set vertex buffer(s), and
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// then configure vertex attributes(s).
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glBindVertexArray(mesh->VAO);
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glBindBuffer(GL_ARRAY_BUFFER, mesh->VBO);
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glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh->EBO);
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glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,
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GL_STATIC_DRAW);
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)0);
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float),
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(void *)(3 * sizeof(float)));
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glEnableVertexAttribArray(1);
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// note that this is allowed, the call to glVertexAttribPointer registered VBO
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// as the vertex attribute's bound vertex buffer object so afterwards we can
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// safely unbind
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// glBindBuffer(GL_ARRAY_BUFFER, 0);
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// remember: do NOT unbind the EBO while a VAO is active as the bound element
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// buffer object IS stored in the VAO; keep the EBO bound.
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// glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
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// You can unbind the VAO afterwards so other VAO calls won't accidentally
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// modify this VAO, but this rarely happens. Modifying other VAOs requires a
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// call to glBindVertexArray anyways so we generally don't unbind VAOs (nor
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// VBOs) when it's not directly necessary.
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// glBindVertexArray(0);
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// Texture Load
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SDL_Surface *image = IMG_Load("./data/testxure.png");
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if (image == NULL) {
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SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't load texture");
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return NULL;
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}
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SDL_FlipSurface(image, SDL_FLIP_VERTICAL);
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GLuint texture;
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glActiveTexture(GL_TEXTURE0);
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glGenTextures(1, &texture);
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// Handle different SDL Surface data types
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// int mode = GL_RGB;
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// if (image->format->BytesPerPixel == 4) {
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int mode = GL_RGBA;
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// mode = GL_RGBA;
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// }
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glBindTexture(GL_TEXTURE_2D, texture);
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// set the texture wrapping parameters
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glTexParameteri(
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GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,
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GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
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// set texture filtering parameters
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexImage2D(GL_TEXTURE_2D, 0, mode, image->w, image->h, 0, mode,
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GL_UNSIGNED_BYTE, image->pixels);
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glGenerateMipmap(GL_TEXTURE_2D);
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SDL_DestroySurface(image);
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return mesh;
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}
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void wn_mesh_draw(wn_mesh *mesh) {
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// draw our first triangle
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glUseProgram(mesh->shader->shaderProgram);
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// seeing as we only have a single VAO there's no need to bind it
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// every time, but we'll do so to keep things a bit more organized
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glBindVertexArray(mesh->VAO);
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// glDrawArrays(GL_TRIANGLES, 0, 6);
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glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
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// glBindVertexArray(0); // no need to unbind it every time
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}
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void wn_mesh_deinit(void *mesh) {
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wn_mesh *cast_mesh = (wn_mesh *)mesh;
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glDeleteVertexArrays(1, &cast_mesh->VAO);
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glDeleteBuffers(1, &cast_mesh->VBO);
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glDeleteBuffers(1, &cast_mesh->EBO);
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}
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