construct view space axes

makefile

@@ -19,7 +19,7 @@ SHADER_TARGETS = $(SHADERS:$(SHADER_ROOT_DIR)/%.glsl=$(SHADER_TARGET_DIR)/%.comp
 TARGET = $(BIN_DIR)/oglc
 
 CC = gcc
-LIBS = `pkg-config --static --libs glew sdl2`
+LIBS = `pkg-config --static --libs glew sdl2 cglm`
 CFLAGS = -I$(SRC_DIR) -Wall
 
 SRC = $(shell find $(SRC_DIR) -name *.c)

res/shader/root/rt.glsl

@@ -2,10 +2,14 @@
 
 layout (location = 1) uniform vec4 t;
 
+layout (location = 2) uniform vec3 w;                       // view space axes
+layout (location = 3) uniform vec3 u;
+layout (location = 4) uniform vec3 v;
+
 layout(local_size_x = 1, local_size_y = 1) in;              // size of local work group - 1 pixel
 layout(rgba32f, binding = 0) uniform image2D img_output;    // rgba32f defines internal format, image2d for random write to output texture
 
-const float INF = 1000000.0f;
+const float INF = 1000.0f;
 
 #include sphere.glsl
 
@@ -54,8 +58,6 @@ Ray createCameraRay(vec2 uv)
     // float2 rd = _CameraLensRadius * randomInUnitDisk();
     // float3 offset = _CameraU * rd.x + _CameraV * rd.y;
 
-    // ...
-
     float max_x = 5.0;
     float max_y = 5.0;
 
@@ -87,16 +89,17 @@ void main()
     hit.normal = vec3(0.0,0.0,0.0);
 
     Sphere sphere;
-    sphere.center = vec3(0.0,0.0,10.0);
-    sphere.radius = 3.0+t.y;
+    //sphere.center = vec3(0.0,0.0,10.0+0.5*t.y);
+    sphere.center = w*-10.0;
+    sphere.radius = 4.0;
 
     // ray-sphere intersection
     intersectSphere(ray, hit, sphere);
 
-    if (hit.distance < INF)
-    {
-        pixel = vec4(t.y,1.0-t.y,1.0,1.0);
-    }
+    float depth = (hit.distance-6.0)/4.0;
+
+    pixel = vec4(t.z,1.0-t.z,depth,1.0);
+    pixel *= (1.0-depth);
 
     // output to a specific pixel in the image
     imageStore(img_output, pixel_coords, pixel);

src/main.c

@@ -23,7 +23,7 @@ int main()
 
     // compile shader programs
     unsigned int computeProgram = compileComputeShaderProgram(
-            "bin/res/compute.compute");
+            "bin/res/rt.compute");
     unsigned int quadProgram = compileQuadShaderProgram(
             "bin/res/shader.vert", 
             "bin/res/shader.frag");
@@ -32,16 +32,30 @@ int main()
     initBuffers();
     setVertexAttributes();
 
+
     // render loop
     while (!checkQuit())
     {
         glUseProgram(computeProgram);
 
         // update uniforms
-        float t = time();
+        float t = time();                                           // time
         float sin_t = sin(t);
         int tLocation = glGetUniformLocation(computeProgram, "t");
-        glUniform4f(tLocation, t, (1.0 + sin_t)*0.5, 0.0f, 0.0f);
+        glUniform4f(tLocation, t, sin_t, (1.0 + sin_t)*0.5, 0.0f);
+
+        // form view space axes
+        vec3 u,v;
+        vec3 up = {0,1.0,0};
+        vec3 w = {0,sin_t*0.1,-1.0};
+        glm_vec3_norm(w);
+        glm_vec3_cross(up,w,u);
+        glm_vec3_norm(u);
+        glm_vec3_cross(w, u, v);
+        int wLocation = glGetUniformLocation(computeProgram, "w");
+        glUniform3f(wLocation+0, w[0], w[1], w[2]);                 // w
+        glUniform3f(wLocation+1, u[0], u[1], u[2]);                 // u
+        glUniform3f(wLocation+2, v[0], v[1], v[2]);                 // v
 
         // dispatch compute shader
         glDispatchCompute((GLuint)width, (GLuint)height, 1);
@@ -51,8 +65,6 @@ int main()
 
         // normal drawing pass
         glUseProgram(quadProgram);
-        //glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
-        //glClear(GL_COLOR_BUFFER_BIT);
         glActiveTexture(GL_TEXTURE0);                                           // use computed texture
         glBindTexture(GL_TEXTURE_2D, textureOutput);
 

src/main.h

@@ -1 +1,4 @@
 #include <stdlib.h>
+
+#include <cglm/vec3.h>
+#include <cglm/cam.h>

todo.md

@@ -1,19 +1,18 @@
 * [x] basic opengl initialisation
-* [-] shader pre-processor
+* [x] shader pre-processor
     * [x] ppp.py
-    * [ ] read root shaders from src/shader/
-    * [ ] read include shaders from src shader/ include
-    * [ ] write processed shaders to bin/res/shader/
-    * [ ] attempt to compile processed shaders
-   
-* [ ] output frame to a file
-    * [ ] detect input keydown s
-    * [ ] get timestamp
-    * [ ] create and write to file (maybe with `stb_image.h`?)
+    * [x] read root shaders
+    * [x] read include shaders
+    * [x] write processed shaders to bin/res/shader/
+    * [x] compile processed shaders
 * [-] render image with compute shader
     * [x] render a texture to a full-screen quad
     * [x] pass uniforms to texture to animate it
-    * [ ] ray tracing time
+    * [-] ray tracing time
+        * [-] perspective
+        * [-] depth
+            * [x] acquire value
+            * [ ] depth texture
         * [ ] acquire randomness
         * [ ] acceleration time ! 
             * [ ] auxiliary textures: g buffer
@@ -22,6 +21,10 @@
         * [ ] mandelbrot
         * [ ] julia
         * [ ] trongle
+* [ ] output frame to a file
+    * [ ] detect input keydown s
+    * [ ] get timestamp
+    * [ ] create and write to file (maybe with `stb_image.h`?)
 * [ ] command line arguments
     * [ ] help
     * [ ] window dimensions