A lot of work

* moved all ugui code to lib/ugui.c3l and made it a library/module
* started work on a sdl3 renderer, with shaders etc
* added the new sdl3.c3l library as a dependency
* makefile is for the renderer

resources/shaders/source/font.frag.glsl

@@ -0,0 +1,18 @@
+#version 330 core
+
+// viewsize.x = viewport width in pixels; viewsize.y = viewport height in pixels
+uniform ivec2 viewsize;
+uniform ivec2 texturesize;
+
+// texture uv coordinate in texture space
+in vec2 uv;
+uniform sampler2DRect ts;
+
+const vec3 textcolor = vec3(1.0, 1.0, 1.0);
+
+
+void main()
+{
+	//gl_FragColor = vec4(1.0f,0.0f,0.0f,1.0f);
+	gl_FragColor = vec4(textcolor, texture(ts, uv));
+}

resources/shaders/source/font.vert.glsl

@@ -0,0 +1,26 @@
+#version 330 core
+
+// viewsize.x = viewport width in pixels; viewsize.y = viewport height in pixels
+uniform ivec2 viewsize;
+uniform ivec2 texturesize;
+
+// both position and and uv are in pixels, they where converted to floats when 
+// passed to the shader
+layout(location = 0) in vec2 position;
+layout(location = 1) in vec2 txcoord;
+
+out vec2 uv;
+
+void main()
+{
+	vec2 v = vec2(float(viewsize.x), float(viewsize.y));
+	
+//	vec2 p = vec2(position.x*2.0f/v.x - 1.0f, position.y*2.0f/v.y - 1.0f);
+	vec2 p = vec2(position.x*2.0/v.x - 1.0, 1.0 - position.y*2.0/v.y);
+	vec4 pos = vec4(p.x, p.y, 0.0f, 1.0f);
+
+	gl_Position = pos;
+	// since the texture is a GL_TEXTURE_RECTANGLE the coordintes do not need to
+	// be normalized
+	uv = vec2(txcoord.x, txcoord.y);
+}

resources/shaders/source/rect.frag.glsl

@@ -0,0 +1,9 @@
+#version 450
+
+layout(location = 0) in vec4 col;
+layout(location = 0) out vec4 fragColor;
+
+void main()
+{
+	fragColor = col;
+}

resources/shaders/source/rect.vert.glsl

@@ -0,0 +1,25 @@
+#version 450
+
+layout(set = 1, binding = 0) uniform Viewport {
+	ivec2 view;
+	ivec2 off;
+};
+
+layout(location = 0) in vec2 position;
+layout(location = 1) in vec2 uv;
+layout(location = 2) in ivec4 color;
+
+layout(location = 0) out vec4 col;
+
+void main()
+{
+	//vec2 shift = vec2(0);
+	vec2 shift;
+	shift.x = float(off.x) / view.x;
+	shift.y = -(float(off.y) / view.y);
+
+	vec2 pos = position + shift;
+
+	gl_Position = vec4(pos.x, pos.y, 0.0, 1.0);
+	col = vec4(color) / 255.0;
+}