Stuff

Signed-off-by: Slendi <slendi@socopon.com>

src/RayExt.c

@@ -0,0 +1,109 @@
+#include "RayExt.h"
+
+#include <raylib.h>
+#include <raymath.h>
+#include <rlgl.h>
+
+#if defined(GRAPHICS_API_OPENGL_ES3)
+static char const *SKYBOX_VS = "#version 300 es\n"
+                               "precision mediump float;\n"
+                               "layout(location=0) in vec3 vertexPosition;\n"
+                               "uniform mat4 mvp;\n"
+                               "out vec3 vDir;\n"
+                               "void main(){ vDir=vertexPosition; "
+                               "gl_Position=mvp*vec4(vertexPosition,1.0); }\n";
+static char const *SKYBOX_FS = "#version 300 es\n"
+                               "precision highp float;\n"
+                               "in vec3 vDir;\n"
+                               "uniform samplerCube environmentMap;\n"
+                               "out vec4 finalColor;\n"
+                               "void main(){ vec3 dir=normalize(vDir); "
+                               "finalColor=texture(environmentMap, dir); }\n";
+#endif
+
+void Skybox_init(Skybox *skybox, char const *fp)
+{
+	if (skybox->ok) {
+		Skybox_destroy(skybox);
+	}
+
+	// 1) Load cubemap from a 3x4 cross image
+	Image img = LoadImage(fp);
+	if (img.width == 0 || img.height == 0) {
+		TraceLog(LOG_ERROR, "Skybox: failed to load image: %s", fp);
+		skybox->ok = false;
+		return;
+	}
+
+	TextureCubemap cubemap
+	    = LoadTextureCubemap(img, CUBEMAP_LAYOUT_AUTO_DETECT);
+	UnloadImage(img);
+	if (cubemap.id == 0) {
+		TraceLog(LOG_ERROR, "Skybox: failed to create cubemap from %s", fp);
+		skybox->ok = false;
+		return;
+	}
+
+	// 2) Make an inward-facing cube mesh
+	Mesh m = GenMeshCube(
+	    2.0f, 2.0f, 2.0f); // size doesn't matter; depth writes off
+	// Invert winding so we see the inside
+	for (int i = 0; i < m.triangleCount; ++i) {
+		unsigned short *idx = &m.indices[i * 3];
+		unsigned short tmp = idx[1];
+		idx[1] = idx[2];
+		idx[2] = tmp;
+	}
+	UploadMesh(&m, false);
+	Model cube = LoadModelFromMesh(m);
+
+	Shader sh = LoadShaderFromMemory(SKYBOX_VS, SKYBOX_FS);
+
+	// make raylib aware which sampler is the cubemap
+	sh.locs[SHADER_LOC_MAP_CUBEMAP] = GetShaderLocation(sh, "environmentMap");
+
+	cube.materials[0].shader = sh;
+
+	// put the cubemap in the expected material slot
+	cube.materials[0].maps[MATERIAL_MAP_CUBEMAP].texture = cubemap;
+
+	// nicer defaults
+	SetTextureWrap(cubemap, TEXTURE_WRAP_CLAMP);
+	SetTextureFilter(cubemap, TEXTURE_FILTER_BILINEAR);
+
+	skybox->cubemap = cubemap;
+	skybox->shader = sh;
+	skybox->cube = cube;
+	skybox->ok = true;
+}
+
+void Skybox_destroy(Skybox *skybox)
+{
+	if (!skybox->ok)
+		return;
+
+	UnloadModel(skybox->cube); // also unloads Mesh
+	UnloadTexture(skybox->cubemap);
+	UnloadShader(skybox->shader);
+
+	*skybox = (Skybox) { 0 };
+}
+
+void Skybox_draw(Skybox const skybox, Vector3 position)
+{
+	if (!skybox.ok)
+		return;
+
+	// Render behind everything without writing depth; cull disabled so we see
+	// inside faces
+	rlDisableColorBlend();
+	rlDisableBackfaceCulling();
+	rlDisableDepthMask();
+
+	DrawModel(skybox.cube, position, 60.0f, (Color) { 255, 255, 255, 255 });
+
+	rlDrawRenderBatchActive();
+	rlEnableDepthMask();
+	rlEnableBackfaceCulling();
+	rlEnableColorBlend();
+}