Added simple render stub to test shader

CMakeLists.txt

@@ -45,6 +45,8 @@ add_executable(bluebell
         src/bluebell.cpp src/bluebell.hpp
         src/pre-compiler.cpp src/pre-compiler.hpp src/compiler.cpp src/compiler.hpp src/spv_meta.cpp src/spv_meta.hpp src/runtime.cpp src/runtime.hpp)
 
+add_executable(render_stub
+        src/render_frame/render_stub.c)
 message(STATUS "Include dirs are ${LLVM_INCLUDE_DIRS}")
 #target_link_libraries(bluebell PkgConfig::shaderc)
 

src/render_frame/render_stub.c

@@ -0,0 +1,85 @@
+//
+// Created by thequux on 5/27/22.
+//
+
+#define _GNU_SOURCE
+#include <malloc.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <err.h>
+
+// render API:
+struct Uniforms {
+    float iResolution[3];
+    float iTime;
+    float iTimeDelta;
+    float iFrame;
+    float iChannelTime[4];
+    float iMouse[4];
+    float iDate[4];
+    float iSampleRate;
+    float iChannelResolution[3][4];
+} uniforms = {
+        .iResolution = {32, 32},
+        .iTime = 0,
+        .iTimeDelta = 0,
+        .iFrame = 0,
+        .iChannelTime = {0,0,0,0},
+        .iMouse = 0,
+        .iDate = {0,0,0,0},
+        .iSampleRate = 0,
+        .iChannelResolution = {}
+};
+
+struct frame_context_t;
+
+void setup_frame(struct frame_context_t* ctx, struct Uniforms *uniforms);
+void render_pixel(struct frame_context_t* ctx, float x, float y, float pixel[3]);
+unsigned int get_context_size(void);
+
+// program utilities
+const char* PPM_HDR = "P6\n32 32\n255\n";
+
+unsigned char frame_buf[32][32][3];
+
+int main(int argc, char** argv) {
+    unsigned header_len = strlen(PPM_HDR);
+    float fdelta = 1. / 30.;
+    struct frame_context_t *ctx = malloc(get_context_size());
+    for (int frame = 0; frame < 100; frame++) {
+        uniforms.iFrame = frame;
+        uniforms.iTimeDelta = fdelta;
+        uniforms.iTime = fdelta * frame;
+        setup_frame(ctx, &uniforms);
+
+        for (int y = 0; y < 32; y++) {
+            for (int x = 0; x < 32; x++) {
+                float pixel[3];
+                unsigned char *pxl_dst = frame_buf[y][x];
+                render_pixel(ctx, (x + 0.5), (y + 0.5), pixel);
+                for (int i = 0; i < 3; i++) {
+                    pixel[i] *= 256;
+                    if (pixel[i] < 0) { pixel[i] = 0; }
+                    if (pixel[i] > 255) { pixel[i] = 255; }
+                    pxl_dst[i] = (unsigned char) pixel[i];
+                }
+            }
+        }
+        char* fname;
+        asprintf(&fname, "render/frame%04d.ppm", frame);
+        int fd = open(fname, O_CREAT | O_WRONLY, 0644);
+        if (fd < 0) {
+            err(1, "Failed to open %s", fname);
+        }
+        write(fd, PPM_HDR, header_len);
+        write(fd, frame_buf, 32*32*3);
+        close(fd);
+        printf("%s\n", fname);
+        free(fname);
+    }
+
+    return 0;
+}