CR

A CPU based 3D renderer. Can be compiled on both Linux with X11(and Wayland I think?) and Windows(see compile instructions).

How to use

Although this repo contains a crWindowing.* and crImaging.* file only the cr.h and cr.c files are needed.

First the CR lib has to be initialized:

#include <stdio.h>
#include <cr.h>

int main(void)
{
	if(!InitCR(800, 600, CR_RGBA, 90, 0.1, 1000.0))
	{
		printf("Failed to initialize CR lib!\n"); // It's recommended to use MessageBox on Windows(idk about Mac)
		return -1;
	}

	printf("Initialized CR lib!\n");
	CleanupCR();

	return 0;
}

After initialization the render destination must be set. This destination has to have either 24 bit depth(CR_RGB) or 32 bit depth(CR_RGBA) depending on what was specified during initialization.
Depending on your window/imaging library it is possible you have to retreive the pointer from the image creation function(Win32) or you have to pass a allocated one in(X11). For both cases you can have a look at the crImaging.c file.

#include <stdio.h>
#include <cr.h>

int main(void)
{
	unsigned char renderTarget[32*32*4] = { 0 }; // In this example the render target is just a raw unsigned char pointer

	if(!InitCR(800, 600, CR_RGBA, 90, 0.1, 1000.0))
	{
		printf("Failed to initialize CR lib!\n"); // It's recommended to use MessageBox on Windows(idk about Mac)
		return -1;
	}

	printf("Initialized CR lib!\n");

	SetRenderDestination(renderTarget);

	CleanupCR();

	return 0;
}

After successfully initializing and setting the destination a pointer/array to some vertex struct has to be created.
Currently a vertex contains a position(vec3) and the uv coordinates(vec2) but in the future it might hold more data.

This mesh data is then passed to the RenderModel function along with the number of elements, a crTransform struct containing information of the position, rotation and scalation of the mesh, the render mode and a function pointer to the fragment shading function.
Currently the only available render mode is RENDER_MODE_MESH as RENDER_MODE_TRIANGLE_STRIP was broken with the introduction of calculated normals(working on getting it running again).

#include <stdio.h>
#include <cr.h>

size_t texture[9] = {
	0xffff0000, 0xff00ff00, 0xff0000ff, 
	0xff00ff00, 0xff0000ff, 0xffff0000, 
	0xff0000ff, 0xffff0000, 0xff00ff00, 
};

size_t fragmentShader(int x, int y, float u, float v, float w)
{
	int tx = 3*u;
	int ty = 2*v;
	return texture[tx+ty*3];
}

int main(void)
{
	unsigned char renderTarget[32*32*4] = { 0 }; // In this example the render target is just a raw unsigned char pointer
	vertex triangle[3] = {
		{ .position={ .x = -0.5, .y = -0.5, .z = 0, .w = 1}, .uv = { .x = 0.0, .y = 0.0 } }, // the positions w always has to be set to 1 initialy
		{ .position={ .x =  0.0, .y =  0.5, .z = 0, .w = 1}, .uv = { .x = 0.5, .y = 1.0 } },
		{ .position={ .x =  0.5, .y = -0.5, .z = 0, .w = 1}, .uv = { .x = 1.0, .y = 0.0 } },
	};
	crTransform triTransform = {
		.position = { .x = 0, .y = 0, .z = 3},
		.rotation = { 0 },
		.scale = { .x = 1, .y = 1, .z = 1},
	};

	if(!InitCR(800, 600, CR_RGBA, 90, 0.1, 1000.0))
	{
		printf("Failed to initialize CR lib!\n"); // It's recommended to use MessageBox on Windows(idk about Mac)
		return -1;
	}

	printf("Initialized CR lib!\n");

	/* Set up a window, create the image... */

	SetRenderDestination(renderTarget);

	while(windowOpen)
	{
		/* render loop */

		triTransform.rotation.y += elapsedTime;
		RenderModel(triangle, 3, triTransform, RENDER_MODE_MESH, fragmentShader);

		/* Display image... */
		CRClearDepthBuffer(); // This doesn't have to be called after displaying the image but should be called before the next render loop, or at the start
	}

	CleanupCR();

	return 0;
}

And that's it! Have fun with my barely functioning render lib!

INFO

Triangle strip are now supported again but need to have back face culling turned of. To see how to do this please have a look at the documentation here.

Compile instructions(for gcc)

For Linux(in this folder setup):

gcc src/*.c -I inc -lX11 -lm -Wall -Werror -o cr.out

For Windows(in this folder setup):

gcc src/*.c -I inc -mwindows -Wall -Werror -o cr.exe

If you want to enable debug view you can define a DEBUG flag:

gcc src/*.c -DDEBUG -I inc -lX11 -lm -Wall -Werror -o cr.out