implement perspective rays
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@ -2,14 +2,19 @@
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layout (location = 1) uniform vec4 t;
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layout (location = 2) uniform vec3 w; // view space axes
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layout (location = 3) uniform vec3 u;
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layout (location = 4) uniform vec3 v;
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layout (location = 2) uniform vec3 _w; // view space axes
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layout (location = 3) uniform vec3 _u;
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layout (location = 4) uniform vec3 _v;
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layout (location = 5) uniform mat4 _cameraInverseProjection;
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layout (location = 6) uniform vec3 _camh;
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layout (location = 7) uniform vec3 _camv;
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layout (location = 8) uniform vec3 _camll;
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layout(local_size_x = 1, local_size_y = 1) in; // size of local work group - 1 pixel
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layout(rgba32f, binding = 0) uniform image2D img_output; // rgba32f defines internal format, image2d for random write to output texture
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const float INF = 1000.0f;
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const float INF = 20.0;
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#include sphere.glsl
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@ -24,6 +29,7 @@ struct RayHit
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vec3 position;
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float distance;
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vec3 normal;
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vec3 albedo;
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};
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void intersectSphere(Ray ray, inout RayHit bestHit, Sphere sphere)
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@ -41,13 +47,14 @@ void intersectSphere(Ray ray, inout RayHit bestHit, Sphere sphere)
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bestHit.distance = t;
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bestHit.position = ray.origin + t*ray.direction;
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bestHit.normal = normalize(bestHit.position-sphere.center);
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bestHit.albedo = sphere.albedo;
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}
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}
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Ray createCameraRay(vec2 uv)
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{
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// transform -1..1 -> 0..1
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//uv = uv*0.5+0.5;
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uv = uv*0.5+0.5;
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//uv.x=1-uv.x;
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// transform camera origin to world space
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@ -58,12 +65,22 @@ Ray createCameraRay(vec2 uv)
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// float2 rd = _CameraLensRadius * randomInUnitDisk();
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// float3 offset = _CameraU * rd.x + _CameraV * rd.y;
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// invert perspective projection of view space position
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//vec3 dir = mul(_cameraInverseProjection, float4(uv, 0.0, 1.0)).xyz;
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// TODO: transform direction from camera to world space (move camera around!)
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vec3 dir;
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dir = uv.x*_camh + uv.y*_camv;
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dir = _camll + uv.x*_camh + uv.y*_camv;
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dir = normalize(dir);
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float max_x = 5.0;
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float max_y = 5.0;
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Ray ray;
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ray.origin = vec3(uv.x * max_x, uv.y * max_y, 0.0);
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ray.direction = vec3(0.0,0.0,1.0); // ortho forwards
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ray.origin = vec3(0.0,0.0,0.0);
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ray.direction = dir;
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return ray;
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}
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@ -87,18 +104,33 @@ void main()
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hit.position = vec3(0.0,0.0,0.0);
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hit.distance = INF;
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hit.normal = vec3(0.0,0.0,0.0);
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hit.albedo = vec3(0.0,0.0,0.0);
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vec3 spheresCenter = _w*-10.0;
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Sphere s1;
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s1.center = spheresCenter+vec3(sin(t.x),0.0,cos(t.x))*2.5;
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s1.radius = 2.0;
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s1.albedo = vec3(1.0,0.0,0.0);
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Sphere s2;
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s2.center = spheresCenter-vec3(sin(t.x),0.0,cos(t.x))*2.5;
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s2.radius = 2.0;
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s2.albedo = vec3(0.0,0.0,1.0);
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Sphere sphere;
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//sphere.center = vec3(0.0,0.0,10.0+0.5*t.y);
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sphere.center = w*-10.0;
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sphere.center = _w*-10.0;
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sphere.center += vec3(0.0,0.0,t.y);
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sphere.radius = 4.0;
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// ray-sphere intersection
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intersectSphere(ray, hit, sphere);
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intersectSphere(ray, hit, s1);
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intersectSphere(ray, hit, s2);
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float depth = (hit.distance-6.0)/4.0;
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// TODO: write depth to texture
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float depth = hit.distance/INF;
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pixel = vec4(t.z,1.0-t.z,depth,1.0);
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pixel = vec4(hit.albedo,1.0);
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pixel *= (1.0-depth);
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// output to a specific pixel in the image
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113
src/main.c
113
src/main.c
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@ -1,6 +1,9 @@
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#include "main.h"
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#include "gfx.h"
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const int WIDTH = 420;
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const int HEIGHT = 420;
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// forward declarations
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// input
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@ -9,16 +12,16 @@ int checkQuit();
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// time
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float time();
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void updateUniforms(GLuint shaderProgram);
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void updateCameraUniforms(GLuint shaderProgram);
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int main()
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{
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int width = 420;
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int height = 420;
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// create a window and opengl context
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SDL_Window* window = gfxInit(width, height);
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SDL_Window* window = gfxInit(WIDTH, HEIGHT);
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// create a texture for the compute shader to write to
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GLuint textureOutput = createWriteOnlyTexture(width, height);
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GLuint textureOutput = createWriteOnlyTexture(WIDTH, HEIGHT);
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printWorkGroupLimits();
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// compile shader programs
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@ -32,33 +35,15 @@ int main()
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initBuffers();
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setVertexAttributes();
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// render loop
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while (!checkQuit())
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{
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glUseProgram(computeProgram);
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// update uniforms
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float t = time(); // time
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float sin_t = sin(t);
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int tLocation = glGetUniformLocation(computeProgram, "t");
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glUniform4f(tLocation, t, sin_t, (1.0 + sin_t)*0.5, 0.0f);
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// form view space axes
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vec3 u,v;
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vec3 up = {0,1.0,0};
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vec3 w = {0,sin_t*0.1,-1.0};
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glm_vec3_norm(w);
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glm_vec3_cross(up,w,u);
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glm_vec3_norm(u);
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glm_vec3_cross(w, u, v);
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int wLocation = glGetUniformLocation(computeProgram, "w");
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glUniform3f(wLocation+0, w[0], w[1], w[2]); // w
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glUniform3f(wLocation+1, u[0], u[1], u[2]); // u
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glUniform3f(wLocation+2, v[0], v[1], v[2]); // v
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updateUniforms(computeProgram);
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// dispatch compute shader
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glDispatchCompute((GLuint)width, (GLuint)height, 1);
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glDispatchCompute((GLuint)WIDTH, (GLuint)HEIGHT, 1);
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// make sure we're finished writing to the texture before trying to read it
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glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
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@ -77,9 +62,85 @@ int main()
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return 0;
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}
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void updateUniforms(GLuint shaderProgram)
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{
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float t = time(); // time
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float sin_t = sin(t);
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int tLocation = glGetUniformLocation(shaderProgram, "t");
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glUniform4f(tLocation, t, sin_t, (1.0 + sin_t)*0.5, 0.0f);
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updateCameraUniforms(shaderProgram);
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}
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void updateCameraUniforms(GLuint shaderProgram)
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{
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// set up perspective projection matrix and its inverse
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mat4 proj, proji;
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float fovy = 60.0; // vertical field of view in deg
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float near = 0.1;
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float far = 1000.0;
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float aspect = (float)WIDTH/(float)HEIGHT;
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glm_perspective(fovy,aspect,near,far,proj); // TODO: radians or degrees??
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glm_mat4_inv(proj, proji);
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int inverseProjLocation = glGetUniformLocation(shaderProgram, "_cameraInverseProjection");
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glUniformMatrix4fv(inverseProjLocation, 1, GL_FALSE, proji[0]);
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// form view space axes
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vec3 u,v;
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vec3 up = {0.0,1.0,0.0};
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vec3 w = {0.0,0.0,-1.0};
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glm_vec3_norm(w);
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glm_vec3_cross(up,w,u);
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glm_vec3_norm(u);
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glm_vec3_cross(w, u, v);
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int wLocation = glGetUniformLocation(shaderProgram, "_w");
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glUniform3f(wLocation+0, w[0], w[1], w[2]); // w
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glUniform3f(wLocation+1, u[0], u[1], u[2]); // u
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glUniform3f(wLocation+2, v[0], v[1], v[2]); // v
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// get camera properties
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float theta = glm_rad(fovy); // convert fovy to radians
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float h = tan(theta*0.5);
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float vph = 2.0*h; // viewport height
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float vpw = aspect*vph; // viewport width
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// TODO: actual focal length lmao
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float f = 1.0;
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// camera axes
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//
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// use vec3_scale instead of vec3_multiply to get scalar multiplication
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// https://cglm.readthedocs.io/en/latest/vec3.html#c.glm_vec3_scale
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vec3 camh={0},
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camv={0},
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camll={0},
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camhh={0},
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camvh={0},
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fw={0};
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glm_vec3_scale(u,f*vpw,camh);
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int camhLocation = glGetUniformLocation(shaderProgram, "_camh");
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glUniform3f(camhLocation, camh[0], camh[1], camh[2]);
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glm_vec3_scale(v,f*vph,camv);
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int camvLocation = camhLocation+1;
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glUniform3f(camvLocation, camv[0], camv[1], camv[2]);
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// camera lower left corner
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// calculate half-axes and w*f to establish 3d position of ll corner in camera space
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glm_vec3_scale(u,f*vpw*0.5,camhh);
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glm_vec3_scale(v,f*vph*0.5,camvh);
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glm_vec3_scale(w,f,fw);
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glm_vec3_sub(camll,camhh,camll);
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glm_vec3_sub(camll,camvh,camll);
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glm_vec3_sub(camll,fw,camll);
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int camllLocation = glGetUniformLocation(shaderProgram, "_camll");
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glUniform3f(camllLocation, camll[0], camll[1], camll[2]);
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}
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float time()
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{
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return (float)SDL_GetTicks() / 1000.0f; // ms / 1000.0 = seconds since start
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// ms / 1000.0 = seconds since start
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return (float)SDL_GetTicks() / 1000.0f;
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}
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int checkQuit()
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@ -2,3 +2,6 @@
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#include <cglm/vec3.h>
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#include <cglm/cam.h>
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#include <cglm/util.h>
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#include <math.h>
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