Made with C99

Description

CursedGL (Cursed Graphics Library) is a notcurses-based software rasterizer inspired by OpenGL 1.X that renders directly to the terminal

Usage

#include <cursedgl.h>

// File that will contain CursedGL text output
#define OUTPUT_FILE "usage.txt"

// Quit rendering if Q is pressed
static bool processInput()
{
    struct ncinput input;
    notcurses_get_nblock(txGetContext(), &input);

    if (input.id == 'q')
        return true;
    return false;
}

// Callback used for getting information from CursedGL
static void messageCallback(enum TXmessageType type, const char* message)
{
    FILE* outputFile = fopen(OUTPUT_FILE, "a");
    if (outputFile) {
        switch (type) {
            case TX_INFO:
                fprintf(outputFile, "[INFO] %s\n", message);
                break;
            case TX_WARNING:
                fprintf(outputFile, "[WARNING] %s\n", message);
                break;
            case TX_ERROR:
                fprintf(outputFile, "[ERROR] %s\n", message);
                break;
        }
        fclose(outputFile);
    }
}

// Spinning triangle
int main(void)
{
    // Set callback to listen to CursedGL's text output
    txSetMessageCallback(messageCallback);

    // Initialize CursedGL
    if (!txInit())
        return -1;

    // Set the color the framebuffer will be cleared with
    txClearColor3f(0.2f, 0.3f, 0.3f);

    // CursedGL uses right-handed coordinate-system
    txTranslate3f(0.0f, 0.0f, -2.0f);

    // Render loop
    while (!processInput()) {

        // Clear the framebuffer
        txClear(TX_COLOR_BIT | TX_DEPTH_BIT);

        // Occupy the whole terminal area
        txViewportMax();

        // Use perspective projection
        txPerspective(TX_PI / 2.0f,
                      txGetFramebufferAspectRatio(),
                      0.1f,
                      100.0f);

        // Specify the vertex data for our triangle
        TXvec4 v0[] = { { -1.0f, -1.0f, 0.0f, 1.0f },
                        {  1.0f,  0.0f, 0.0f, 1.0f } };
        TXvec4 v1[] = { {  1.0f, -1.0f, 0.0f, 1.0f },
                        {  0.0f,  1.0f, 0.0f, 1.0f } };
        TXvec4 v2[] = { {  0.0f,  1.0f, 0.0f, 1.0f },
                        {  0.0f,  0.0f, 1.0f, 1.0f } };

        // Rotate the triangle continuously around y-axis
        txRotate4f(0.01f, 0.0f, 1.0f, 0.0f);

        // Draw the triangle with one of the predefined
        // vertex-attribute configurations (here we use
        // TX_POSITION_COLOR, for more see enum TXvertexInfo
        // in rasterizer.h)
        txDrawTriangle(v0, v1, v2, TX_POSITION_COLOR);

        // Swap the front and back framebuffers
        txSwapBuffers();
    }

    // Free memory used for rendering
    txEnd();

    // Success
    return 0;
}

Output

usage.mp4

Features

• Supports points, lines, line-loops, line-strips, triangles, triangle-fans, triangle-strips, and quads
• In addition to the above some basic shapes like cubes and planes are provided out-of-the-box
• Face Culling
• Triangle Clipping
• Perspective-Correct Vertex-Attribute Interpolation
• Early Depth Testing
• 3 Shading Modes:
  • Unlit
  • Flat
  • Smooth
• Built-in Math Library
• Right-handed Coordinate System
• Multi-threaded rendering
• Double-buffering
• API similar to OpenGL's Immediate Mode Interface
• 3 Supported Light Types:
  • Directional
  • Point
  • Spot
• Matrix Stacks

Known Bugs And Issues

• No texture support yet
• More sophisticated multi-threading system would be better
• Math library needs SIMD implementation
• No stencil buffer
• No blending
• Code needs testing

Building

Linux

Make sure to have GCC, notcurses, and cmake installed.

$ git clone https://github.com/saccharineboi/CursedGL.git
$ cd CursedGL
$ mkdir build && cd build
$ cmake ..
$ make

Windows 10, 11

Windows 10 and 11 come pre-installed with Linux kernel out-of-the-box.

You need to enable WSL2 and install Ubuntu from the Windows Store.

This video will be helpful.

After you've got everything working, follow the instructions for the linux users above.

Learning

Check the examples/ folder for code samples

Check the comments in the source files under src/ folder

Contact

Grab my public key here and send me an email.

PGP fingerprint: 693E AD50 5142 9D3F 74D9 F415 869B 4A61 D04F AD71

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License

Copyright (C) 2022 saccharineboi

CursedGL is dual-licensed under GPLv3 and LGPLv3. Choose whichever you like.