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openglopengl-4

How to use glClearBufferData to initialize a buffer

GLuint buffer;
glCreateBuffers(1, &buffer);
glNamedBufferStorage(buffer, 1024, NULL, GL_MAP_WRITE_BIT | GL_MAP_READ_BIT | GL_DYNAMIC_STORAGE_BIT);
unsigned int x = 0x01010101;
glBindBuffer(GL_ARRAY_BUFFER, buffer);

glClearBufferData(GL_ARRAY_BUFFER, GL_R32UI, GL_RED, GL_UNSIGNED_INT, &x);
int* p = (int*)glMapBuffer(GL_ARRAY_BUFFER, GL_READ_WRITE);
for (int i = 0; i < 4; ++i)
    cout << hex << p[i] << " ";
glUnmapBuffer(GL_ARRAY_BUFFER);

However, the output is '1010102' rather than '1010101'.

Solution 
  • glClearBufferData(GL_ARRAY_BUFFER, GL_R32UI, GL_RED, GL_UNSIGNED_INT, &x);

    The proper format parameter should be GL_RED_INTEGER, not GL_RED.