Hi guys!
So I am using this library for my GUI: nuklear. I want to draw an image onto a nuklear window. I am creating my image as a 1D array, filled with RGBA pixels [R, G, B, A, R, G, B, A, …]. Next I “render” this array onto an OpenGL texture, and pass it on to a nuklear function to draw this texture onto a window.
The full code with details is following:
struct nk_command_buffer *canvas;
const struct nk_color grid_color = nk_rgba(255, 255, 255, 255);
struct nk_vec2 upperCoord;
const unsigned int WIDTH_IMG = 80;
const unsigned int HEIGHT_IMG = 80;
unsigned char imageData[WIDTH_IMG * HEIGHT_IMG * 4];
struct nk_image myImage;
struct nk_rect total_space;
void draw_line(struct nk_context* ctx)
{
canvas = nk_window_get_canvas(ctx);
total_space = nk_window_get_content_region(ctx);
// Draw simple line.
upperCoord = nk_window_get_content_region_min(ctx);
nk_stroke_line(canvas, upperCoord.x + 0, upperCoord.y + 0, upperCoord.x + 10, upperCoord.y + 10, 1.0f, grid_color);
// Create an image. For now all pixels are the same.
int i = 0;
for (unsigned int y = 0; y < HEIGHT_IMG; ++y){
for (unsigned int x = 0; x < WIDTH_IMG; ++x){
imageData[i] = 174;
imageData[i + 1] = 79;
imageData[i + 2] = 206;
imageData[i + 3] = 255;
i += 4;
}
}
// creating a texture
unsigned int texture = 42;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
// set necessary texture parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// allocate memory and set texture data
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, WIDTH_IMG, HEIGHT_IMG, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
// render texture inside current nuklear window
myImage = nk_image_id((int)texture);
nk_draw_image(canvas, total_space, &myImage, grid_color);
// delete texture
glDeleteTextures(1, &texture);
}
The most important part is:
// allocate memory and set texture data
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, WIDTH_IMG, HEIGHT_IMG, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
// render texture inside current nuklear window
myImage = nk_image_id((int)texture);
nk_draw_image(canvas, total_space, &myImage, grid_color);
// delete texture
glDeleteTextures(1, &texture);
The full program listing (along with instructions for running it) is at https://github.com/mandelbulb-4d/mandelbulb-4d/blob/a3b9ee89a5ed3f3046204bcaa3e8a6a9c52f7a0c/src2/simple_window/drawing.cpp#L51.
The result is somewhat unexpected random gibberish:
[ATTACH=CONFIG]1499[/ATTACH]
What might be the problem? Please help me! Will be thankful for any input. 