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Hello community, long time no see. I am working on my own graphical user interface, for my super duper rpg game :). The use separate textures for each button state, etc. I consider it not effective! It is better to load the texture with the atlas of the whole GUI once. And use her. In order to draw a texture from the atlas, we need to slightly modify the standard shader (drawimage), and save it under a different name (drawimagerect). Shader #version 400 uniform vec4 drawcolor; uniform sampler2D texture0; uniform vec4 rect; in vec2 vTexCoords0; out vec4 fragData0; void main(void) { ivec2 ts = textureSize(texture0, 0); vec4 coord = vec4(rect.x / ts.x, rect.y / ts.y, rect.z / ts.x, rect.w / ts.y); vec2 uv = coord.xy + (vTexCoords0 * coord.zw); fragData0 = drawcolor * texture(texture0,uv); } Now we can draw a texture from the atlas: void drawImageRect(Texture* texture, float x, float y, Vec4 rect) { Context* context = Context::GetCurrent(); context->SetShader(Shader::Load("Shaders/Drawing/drawimagerect.shader")); context->GetShader()->SetVec4("rect", rect); context->DrawImage(texture, x, y, rect.z, rect.w); context->SetShader(NULL); } void drawImageRect(Texture* texture, float x, float y, float width, float height, Vec4 rect) { Context* context = Context::GetCurrent(); context->SetShader(Shader::Load("Shaders/Drawing/drawimagerect.shader")); context->GetShader()->SetVec4("rect", rect); context->DrawImage(texture, x, y, width, height); context->SetShader(NULL); } Animation To play the animation we need to get the coordinates of all the frames in the atlas. Naturally, we won't do this manually, will write a small algorithm. bool isEmptyFrame(char* pixels, int textureWidth, iVec2 position, iVec2 frameSize, const bool alpha=true, const iVec3 colorBg=iVec3()) { unsigned char r, g, b, a; int level = 0; for (int y = position.y; y < position.y + frameSize.y; y++) { for (int x = position.x; x < position.x + frameSize.x; x++) { int p = (y * textureWidth + x) * 4; memcpy(&r, pixels + p + 0, 1); memcpy(&g, pixels + p + 1, 1); memcpy(&b, pixels + p + 2, 1); memcpy(&a, pixels + p + 3, 1); if (!alpha) { if ((int)r == colorBg.r && (int)g == colorBg.g && (int)b == colorBg.b) { level++; } else { return false; } } else { if ((int)a == 0) { level++; } else { return false; } } } } float percent = (float)((float)level / (float)(frameSize.x * frameSize.y)) * 100.0f; if (percent >= 100.0f) { return true; } return false; } void getFrames(Texture* texture, iVec2 framesize, std::vector<Vec4> &frames) { if (texture == nullptr) return; int horizontLine = texture->GetWidth() / framesize.x; int verticalLine = texture->GetHeight() / framesize.y; int frameCount = horizontLine * verticalLine; int currentHorizont = 0; int currentVertical = 0; iVec2 framePosition = iVec2(); iVec2 frameSize = framesize; char* pixels = (char*)malloc(texture->GetMipmapSize(0) * 8); texture->GetPixels(pixels); System::Print((std::string)"Get frames from texture atlas \"" + texture->GetPath() + "\"..."); // Push first frame int skipCount = 0; if (!isEmptyFrame(pixels, texture->GetWidth(), framePosition, frameSize)) { frames.push_back(Vec4((float)framePosition.x, (float)framePosition.y, (float)frameSize.x, (float)frameSize.y)); } else { skipCount++; System::Print((std::string)"Frame #0" + " is empty. (skip)"); } for (int i = 1; i < frameCount; i++) { if (currentHorizont < horizontLine - 1) { currentHorizont++; framePosition.x = frameSize.x * currentHorizont; } else { if (currentVertical < verticalLine - 1) { currentVertical++; framePosition.x = 0; framePosition.y = frameSize.y * currentVertical; currentHorizont = 0; } } if (!isEmptyFrame(pixels, texture->GetWidth(), framePosition, frameSize)) { frames.push_back(Vec4((float)framePosition.x, (float)framePosition.y, (float)frameSize.x, (float)frameSize.y)); } else { skipCount++; System::Print((std::string)"Frame #" + std::to_string(i) + " is empty. (skip)"); } } System::Print((std::string)"Frame count: " + std::to_string(frames.size()) + ", skip: " + std::to_string(skipCount)); free(pixels); } Now that we have all the frames, we can play the animation. Texture* atlas = Texture::Load("Textures/atlas.tex"); std::vector<Vec4> frames; getFrames(atlas, iVec2(96, 96), frames); float frame = 0.0f; float frameend = frames.size(); float framebegin = 0.0f; float speed = 0.1f; //Loop frame += Time::GetSpeed() * speed; frame = fmodf(frame, frameend - framebegin) + framebegin; //Draw drawImageRect(atlas, 25.0f, 25.0f, frames[(int)frame]); Updates: [04.04.2020] [+] Added check for empty frames.

So I was reading a something from a post on one of Unity's forums (I'm not interested in the engine, but some of the discussions there are helpful), and atlas texturing seems to be a big thing there. I had no idea that one large texture that combined multiple small textures could improve performance substantially. Anyway, how does Leadwerks draw textures under the hood? Does it go through all draw calls like Unity (and thus atlas texturing is important)? Also, are textures dynamically freed when the last instance of a material is hidden from view? Thanks in advance for any feedback! I'm trying to determine how to best achieve certain levels of performance in the long run.