我正在使用 GLKit 绘制像素。如果我有,我可以成功地在 (10, 10) 坐标处绘制像素:
glClearColor(0.65f, 0.65f, 0.65f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Prepare the effect for rendering
[self.effect prepareToDraw];
GLfloat points[] =
{
10.0f, 10.0f,
};
glClearColor(1.0f, 1.0f, 0.0f, 1.0f);
GLuint bufferObjectNameArray;
glGenBuffers(1, &bufferObjectNameArray);
glBindBuffer(GL_ARRAY_BUFFER, bufferObjectNameArray);
glBufferData(
GL_ARRAY_BUFFER,
sizeof(points),
points,
GL_STATIC_DRAW);
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(
GLKVertexAttribPosition,
2,
GL_FLOAT,
GL_FALSE,
2*4,
NULL);
glDrawArrays(GL_POINTS, 0, 1);
但是我想在运行时决定要绘制像素的数量和确切位置,所以我尝试了这个,但它在 (10, 0) 处绘制像素,这里出了点问题:
glClearColor(0.65f, 0.65f, 0.65f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Prepare the effect for rendering
[self.effect prepareToDraw];
GLfloat *points = (GLfloat*)malloc(sizeof(GLfloat) * 2);
for (int i=0; i<2; i++) {
points[i] = 10.0f;
}
glClearColor(1.0f, 1.0f, 0.0f, 1.0f);
GLuint bufferObjectNameArray;
glGenBuffers(1, &bufferObjectNameArray);
glBindBuffer(GL_ARRAY_BUFFER, bufferObjectNameArray);
glBufferData(
GL_ARRAY_BUFFER,
sizeof(points),
points,
GL_STATIC_DRAW);
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(
GLKVertexAttribPosition,
2,
GL_FLOAT,
GL_FALSE,
2*4,
NULL);
glDrawArrays(GL_POINTS, 0, 1);
请帮帮我。
编辑: 问题 实际上问题是:我不知道有什么区别:
GLfloat points[] =
{
10.0f, 10.0f,
};
和
GLfloat *points = (GLfloat*)malloc(sizeof(GLfloat) * 2);
for (int i=0; i<2; i++) {
points[i] = 10.0f;
}