CPU Rasterizer

A tile based cpu rasterizer

Platform

Windows
Linux
MacOS

Usage

download zip or clone CPU-Rasterizer
run 'setup.bat' or type 'premake vs2017/vs2019'

Hello Triangle

#include "CGL.h"
#include "HelloTriangleShader.hpp"

int main()
{
	size_t w = 600;
	size_t h = 400;
	// initialize window
	cglInitWindow("Demo", w, h);

	// set viewport
	cglSetViewPort(0, 0, w, h);

	// resize callback
	cglAddResizeEvent([](size_t resized_w, size_t resized_h, void* ud)
	{
		UNUSED(ud);
		cglSetViewPort(0, 0, resized_w, resized_h);
	}, nullptr);

	HelloTriangleShader shader;
	uint32_t shader_id;
	cglCreateProgram(&shader, shader_id);

	// a triangle 
	cglVert v1(cglVec4(-0.5f, -0.5f, 0.0f, 1.0f), cglVec3Zero, cglVec2Zero);
	cglVert v2(cglVec4(0.5f, -0.5f, 0.0f, 1.0f), cglVec3Zero, cglVec2Zero);
	cglVert v3(cglVec4(0.0f, 0.5f, 0.0f, 1.0f), cglVec3Zero, cglVec2Zero);

	std::vector<cglVert> vertex_buffer = {v1, v2, v3};
	std::vector<size_t> index_buffer = { 0, 1, 2 };

	auto vid = cglBindVertexBuffer(vertex_buffer);
	auto iid = cglBindIndexBuffer(index_buffer);

	// setup shader properties
	cglUniformMatrix4fv(shader_id, mat_model_prop, cglMat4Identity);
	cglUniformMatrix4fv(shader_id, mat_view_prop, cglMat4Identity);
	cglUniformMatrix4fv(shader_id, mat_projection_prop, cglMat4Identity);
	cglUniformMatrix4fv(shader_id, mat_vp_prop, cglMat4Identity);
	cglUniformMatrix4fv(shader_id, mat_mvp_prop, cglMat4Identity);

	cglDisable(cglPipelineFeature::kBlending);
	cglDisable(cglPipelineFeature::kFaceCulling);
	cglDepthFunc(cglCompareFunc::kAlways);

	// set background color
	cglSetClearColor(tinymath::kColorBlue);

	while (cglIsMainWindowOpen())
	{
		// clear window buffer
		cglClearMainWindow();

		// clear buffer
		cglClearBuffer(cglFrameContent::kColor | cglFrameContent::kDepth | cglFrameContent::kStencil);

		cglUseProgram(shader_id);

		cglUseVertexBuffer(vid);
		cglUseIndexBuffer(iid);

		// draw primitive
		cglDrawPrimitive();

		// fence primitive tasks
		cglFencePrimitives();

		// fence pixel tasks
		cglFencePixels();

		cglSwapBuffer(true);
	}

	cglCloseMainWindow();

	return 0;
}

Shader:

#pragma once
#include "Shader.hpp"

using namespace CpuRasterizor;
using namespace tinymath;

class HelloTriangleShader : public Shader
{
public:
	HelloTriangleShader() : Shader("sample_shader") {}

	v2f vertex_shader(const a2v& input) const
	{
		v2f o;
		auto opos = vec4f(input.position.x, input.position.y, input.position.z, 1.0f);
		auto m = model();
		auto vp = vp_matrix();
		auto wpos = m * opos;
		auto cpos = vp * wpos;
		o.position = cpos;
		return o;
	}

	Color fragment_shader(const v2f& input) const
	{
		UNUSED(input);

		// draw a white triangle
		return kColorWhite;
	}
};

Result:

Texture Mapping

#include "CGL.h"
#include "HelloTextureShader.hpp"

int main()
{
	size_t w = 600;
	size_t h = 400;
	// initialize window
	cglInitWindow("Demo", w, h);

	// set viewport
	cglSetViewPort(0, 0, w, h);

	// resize callback
	cglAddResizeEvent([](size_t resized_w, size_t resized_h, void* ud)
	{
		UNUSED(ud);
		cglSetViewPort(0, 0, resized_w, resized_h);
	}, nullptr);

	HelloTextureShader shader;
	uint32_t shader_id;
	cglCreateProgram(&shader, shader_id);

	// a triangle 
	cglVert v1(cglVec4(-0.5f, -0.5f, 0.0f, 1.0f), cglVec3Zero, cglVec2(0.0f, 0.0f));
	cglVert v2(cglVec4(0.5f, -0.5f, 0.0f, 1.0f), cglVec3Zero, cglVec2(1.0f, 0.0f));
	cglVert v3(cglVec4(0.0f, 0.5f, 0.0f, 1.0f), cglVec3Zero, cglVec2(0.5f, 1.0f));

	std::vector<cglVert> vertex_buffer = { v1, v2, v3 };
	std::vector<size_t> index_buffer = { 0, 1, 2 };

	auto vid = cglBindVertexBuffer(vertex_buffer);
	auto iid = cglBindIndexBuffer(index_buffer);

	// setup shader properties
	cglUniformMatrix4fv(shader_id, mat_model_prop, cglMat4Identity);
	cglUniformMatrix4fv(shader_id, mat_view_prop, cglMat4Identity);
	cglUniformMatrix4fv(shader_id, mat_projection_prop, cglMat4Identity);
	cglUniformMatrix4fv(shader_id, mat_vp_prop, cglMat4Identity);
	cglUniformMatrix4fv(shader_id, mat_mvp_prop, cglMat4Identity);

	cglDisable(cglPipelineFeature::kBlending);
	cglDisable(cglPipelineFeature::kFaceCulling);
	cglDepthFunc(cglCompareFunc::kAlways);

	auto tex = std::make_shared<Texture>(64, 64, cglTextureFormat::kRGB);

	// generate a checkerboard texture
	for (size_t r = 0; r < 64; ++r)
	{
		for (size_t c = 0; c < 64; ++c)
		{
			auto val = ((r & 0x8) == 0) ^ ((c & 0x8) == 0);
			tex->write(r, c, { (float)val, (float)val, (float)val, 1.0f});
		}
	}

	// todo: strinify the key
	shader.local_properties.set_texture(123, tex);

	// set background color
	cglSetClearColor(tinymath::kColorBlue);

	while (cglIsMainWindowOpen())
	{
		// clear window buffer
		cglClearMainWindow();

		// clear buffer
		cglClearBuffer(cglFrameContent::kColor | cglFrameContent::kDepth | cglFrameContent::kStencil);

		cglUseProgram(shader_id);

		cglUseVertexBuffer(vid);
		cglUseIndexBuffer(iid);

		// draw primitive
		cglDrawPrimitive();

		// fence primitive tasks
		cglFencePrimitives(); 

		// fence pixel tasks
		cglFencePixels(); 

		cglSwapBuffer(true);
	}

	cglCloseMainWindow();

	return 0;
}

Shader:

#pragma once
#include "Shader.hpp"

using namespace CpuRasterizor;
using namespace tinymath;

class HelloTextureShader : public Shader
{
public:
	HelloTextureShader() : Shader("sample_shader") {}

	v2f vertex_shader(const a2v& input) const
	{
		v2f o;
		auto opos = vec4f(input.position.x, input.position.y, input.position.z, 1.0f);
		auto m = model();
		auto vp = vp_matrix();
		auto wpos = m * opos;
		auto cpos = vp * wpos;
		o.position = cpos;
		o.uv = input.uv;
		return o;
	}

	Color fragment_shader(const v2f& input) const
	{
		UNUSED(input);

		// visualize uv
		//return input.uv;

		// sample texture
		Color c;
		if (local_properties.has_texture(123))
		{
			local_properties.get_texture(123)->sample(input.uv.x, input.uv.y, c);
		}

		return c;
	}
};

Result:

UV can be visualized by:

Color fragment_shader(const v2f& input) const
{
	return input.uv;
}

Result:

Simple Lighting

#include "CGL.h"
#include "HelloLightingShader.hpp"

HelloLightingShader shader;

cglVec3 spherical_coord(float theta, float phi)
{
	cglVec3 ret;
	ret.x = cglCos(theta) * cglCos(phi);
	ret.y = cglSin(theta);
	ret.z = cglCos(theta) * cglSin(phi);
	return cglNormalize(ret);
}

int main()
{
	size_t w = 600;
	size_t h = 400;
	// initialize window
	cglInitWindow("Demo", w, h);

	// set viewport
	cglSetViewPort(0, 0, w, h);

	// resize callback
	cglAddResizeEvent([](size_t resized_w, size_t resized_h, void* ud)
	{
		UNUSED(ud);
		cglSetViewPort(0, 0, resized_w, resized_h);
	}, nullptr);

	// setup shader properties
	cglVec3 cam_pos = cglVec3(1.5f, 1.5f, 1.5f);
	cglVec3 cube_pos = cglVec3Zero;
	cglVec3 light_direction;	

	float l_theta = 0.0f;
	float l_phi = 0.0f;

	light_direction.x = 0.0f;
	light_direction.y = 0.5f;
	light_direction.z = 1.0f;

	float near = 0.05f;
	float far = 100.0f;

	cglMat4 model = cglTranslation(cube_pos);
	cglMat4 view = cglLookat(cam_pos, cube_pos, cglVec3Up);
	cglMat4 proj = cglPerspective(60.0f, (float)w / (float)h, near, far);

	uint32_t shader_id;
	cglCreateProgram(&shader, shader_id);

	cglUniformMatrix4fv(shader_id, mat_model_prop, model);
	cglUniformMatrix4fv(shader_id, mat_view_prop, view);
	cglUniformMatrix4fv(shader_id, mat_projection_prop, proj);
	cglUniformMatrix4fv(shader_id, mat_vp_prop, proj * view);
	cglUniformMatrix4fv(shader_id, mat_mvp_prop, proj * view * model);
	cglUniform4fv(shader_id, cam_position_prop, cam_pos);
	cglUniform4fv(shader_id, albedo_prop, cglVec4(0.5f, 0.0f, 0.0f, 1.0f));
	cglUniform4fv(shader_id, light_direction_prop, light_direction);
	cglUniform4fv(shader_id, light_color_prop, cglVec4(1.0f, 1.0f, 1.0f, 1.0f));
	cglUniform1f(shader_id, light_intensity_prop, 1.0f);

	cglDisable(cglPipelineFeature::kBlending);
	cglEnable(cglPipelineFeature::kFaceCulling);
	cglCullFace(cglFaceCulling::Back);
	cglDepthFunc(cglCompareFunc::kLess);

	std::vector<Vertex> vert;
	std::vector<size_t> ind;

	// construct a sphere
	float step = TWO_PI / 64.0f;
	for (float phi = 0.0f; phi < TWO_PI; phi += step)
	{
		for (float theta = -HALF_PI; theta < HALF_PI; theta += step)
		{
			float phi0 = phi;
			float phi1 = phi + step;

			float theta0 = theta;
			float theta1 = theta + step;

			auto pos0 = spherical_coord(theta0, phi0);

			auto pos1 = spherical_coord(theta1, phi0);

			auto pos2 = spherical_coord(theta1, phi1);

			auto pos3 = spherical_coord(theta0, phi1);

			Vertex v0, v1, v2, v3;
			v0.position = pos0;
			v0.normal = pos0;
			v1.position = pos1;
			v1.normal = pos1;
			v2.position = pos2;
			v2.normal = pos2;
			v3.position = pos3;
			v3.normal = pos3;

			ind.push_back(vert.size());
			vert.push_back(v0);
			ind.push_back(vert.size());
			vert.push_back(v1);
			ind.push_back(vert.size());
			vert.push_back(v2);
			ind.push_back(vert.size());
			vert.push_back(v0);
			ind.push_back(vert.size());
			vert.push_back(v2);
			ind.push_back(vert.size());
			vert.push_back(v3);
		}
	}

	auto vid = cglBindVertexBuffer(vert);
	auto iid = cglBindIndexBuffer(ind);

	// set background color
	cglSetClearColor(tinymath::kColorBlue);

	while (cglIsMainWindowOpen())
	{
		// clear window buffer
		cglClearMainWindow();

		// clear buffer
		cglClearBuffer(cglFrameContent::kColor | cglFrameContent::kDepth | cglFrameContent::kStencil);

		// rotate light
		l_theta += 0.01f;
		l_phi += 0.01f;
		light_direction.x = cglCos(l_theta) * cglCos(l_phi);
		light_direction.y = cglSin (l_theta);
		light_direction.z = cglCos(l_theta) * cglSin(l_phi);
		light_direction = cglNormalize(light_direction);

		shader.local_properties.set_float4(light_direction_prop, light_direction);

		cglUseProgram(shader_id);

		cglUseVertexBuffer(vid);
		cglUseIndexBuffer(iid);

		// draw primitive
		cglDrawPrimitive();

		// fence primitive tasks
		cglFencePrimitives();

		// fence pixel tasks
		cglFencePixels();

		cglSwapBuffer(true);
	}

	cglCloseMainWindow();

	return 0;
}

Shader:

#pragma once
#include "Shader.hpp"

using namespace CpuRasterizor;
using namespace tinymath;

class HelloLightingShader : public Shader
{
public:
	HelloLightingShader() : Shader("sample_shader") {}

	v2f vertex_shader(const a2v& input) const
	{
		v2f o;
		auto opos = vec4f(input.position.x, input.position.y, input.position.z, 1.0f);
		auto m = model();
		auto vp = vp_matrix();
		auto wpos = m * opos;
		auto v = view();
		auto p = projection();
		auto cpos = vp * wpos;
		o.position = cpos;
		o.uv = input.uv;
		mat3x3 normal_matrix = mat4x4_to_mat3x3(transpose(inverse(m)));
		o.normal = normal_matrix * input.normal;
		return o;
	}

	Color fragment_shader(const v2f& input) const
	{
		vec4f albedo = local_properties.get_float4(albedo_prop);
		vec4f light_color = local_properties.get_float4(light_color_prop);
		float intensity = local_properties.get_float(light_intensity_prop);

		vec3f normal = input.normal;
		vec3f light_dir = local_properties.get_float4(light_direction_prop).xyz;
		float ndl = dot(normal, light_dir);

		return albedo * light_color * ndl * intensity;
	}
};

Result: