Higher level operations for OpenGLES in C(99)
With clib:
$ clib install glisy/glisy --saveFrom source:
$ make
$ make installWIP - Active development
The following example draws a rotating cube:
with the following shader code:
vertex:
#version 400
precision mediump float;
uniform mat4 projection;
uniform mat4 model;
uniform mat4 view;
in vec3 position;
void main(void) {
gl_Position = projection * view * model * vec4(position, 1.0);
}fragment:
#version 400
precision mediump float;
uniform vec3 color;
out vec4 fragColor;
void main(void) {
fragColor = vec4(color, 1);
}and the following C code:
#include <glisy/geometry.h>
#include <glisy/camera.h>
#include <glisy/color.h>
#include <glisy/math.h>
#include "util.h"
#define WINDOW_NAME "CubeExample"
#define WINDOW_WIDTH 640
#define WINDOW_HEIGHT 640
// model
typedef struct Cube Cube;
struct Cube {
// glisy
GlisyGeometry geometry;
GlisyUniform model;
// model
vec3 position;
mat4 transform;
mat4 rotation;
// vao
int faceslen;
};
static mat4 transform;
static float aspect = (float) WINDOW_WIDTH / (float) WINDOW_HEIGHT;
static float near = 1.0;
static float far = 1000.0;
static float fov = M_PI / 2.0;
static Cube cube;
static GlisyProgram program;
static GlisyCamera camera;
static GLFWwindow *window;
static void InitializeCube(Cube *cube);
static void UpdateCube(Cube *cube);
static void RotateCube(Cube *cube, float radians, vec3 axis);
void InitializeCube(Cube *cube) {
static const vec3 vertices[] = {
vec3(-0.5, -0.5, +0.5),
vec3(+0.5, -0.5, +0.5),
vec3(-0.5, +0.5, +0.5),
vec3(+0.5, +0.5, +0.5),
vec3(-0.5, -0.5, -0.5),
vec3(+0.5, -0.5, -0.5),
vec3(-0.5, +0.5, -0.5),
vec3(+0.5, +0.5, -0.5),
};
static const GLushort faces[] = {
0, 1, 3, 0, 3, 2,
1, 5, 7, 1, 7, 3,
5, 4, 6, 5, 6, 7,
4, 0, 2, 4, 2, 6,
4, 5, 1, 4, 1, 0,
2, 3, 7, 2, 7, 6,
};
// init color
GlisyColor color;
glisyColorInit(&color, "blue", 0);
// init uniforms
GlisyUniform ucolor;
glisyUniformInit(&ucolor, "color", GLISY_UNIFORM_VECTOR, 3);
glisyUniformInit(&cube->model, "model", GLISY_UNIFORM_MATRIX, 4);
// set uniforms
glisyUniformSet(&ucolor, &(vec3){color.r, color.g, color.b}, sizeof(vec3));
glisyUniformBind(&ucolor, 0);
cube->position = vec3(0, 0, 0);
cube->faceslen = sizeof(faces) / sizeof(GLushort);
GLuint size = sizeof(vertices);
GlisyVAOAttribute position;
memset(&position, 0, sizeof(position));
position.buffer.data = (void *) vertices;
position.buffer.type = GL_FLOAT;
position.buffer.size = size;
position.buffer.usage = GL_STATIC_DRAW;
position.buffer.dimension = 3;
// init matrices
mat4_identity(cube->transform);
mat4_identity(cube->rotation);
// init vao attributes
glisyGeometryInit(&cube->geometry);
glisyGeometryAttr(&cube->geometry, "position", &position);
glisyGeometryFaces(&cube->geometry,
GL_UNSIGNED_SHORT,
cube->faceslen,
(void *) faces);
// update geometry with attributes and faces
glisyGeometryUpdate(&cube->geometry);
// update cube model
UpdateCube(cube);
}
void UpdateCube(Cube *cube) {
mat4 model = mat4_multiply(mat4(), cube->rotation);
glisyUniformSet(&cube->model, &model, sizeof(model));
glisyUniformBind(&cube->model, 0);
}
void DrawCube(Cube *cube) {
UpdateCube(cube);
glisyGeometryBind(&cube->geometry, 0);
glisyGeometryDraw(&cube->geometry, GL_TRIANGLES, 0, cube->faceslen);
glisyGeometryUnbind(&cube->geometry);
}
void
RotateCube(Cube *cube, float radians, vec3 axis) {
(void) mat4_rotate(cube->rotation, radians, axis);
}
int main(void) {
// init gl
GLFW_SHELL_CONTEXT_INIT(3, 2);
GLFW_SHELL_WINDOW_INIT(window, WINDOW_WIDTH, WINDOW_HEIGHT);
glfwSetWindowUserPointer(window, &camera);
// create shader program (util.h)
program = CreateProgram("cube.v.glsl", "cube.f.glsl");
// init objects
InitializeCube(&cube);
// bind current shader program
glisyProgramBind(&program);
// configure camera
glisyCameraInitialize(&camera);
// move camera away from cube
camera.position = vec3(0, 0, -2);
// update camera state (util.h)
UpdateCamera(&camera, &program, mat4(), fov, aspect, near, far);
GLFW_SHELL_RENDER(window, {
const float angle = glfwGetTime() * 45.0f;
const float radians = dtor(angle);
// width/height from `GLFW_SHELL_RENDER' macro
aspect = (float) width / (float) height;
// update camera state (util.h)
UpdateCamera(&camera, &program, mat4(), fov, aspect, near, far);
//rotate cube in opposite direction
RotateCube(&cube, radians, vec3_negate(vec3(0, 1, 0)));
// draw cube to screen
DrawCube(&cube);
});
return 0;
}MIT