opengl: more funcs

src/main.zig

@@ -22,7 +22,7 @@ pub fn main() !void {
     window.setSizeCallback((struct {
         fn callback(_: glfw.Window, width: i32, height: i32) void {
             std.log.info("set viewport {} {}", .{ width, height });
-            gl.c.glViewport(0, 0, width, height);
+            try gl.viewport(0, 0, width, height);
         }
     }).callback);
 
@@ -46,12 +46,11 @@ pub fn main() !void {
     defer tex.destroy();
     var texbind = try tex.bind(gl.c.GL_TEXTURE_2D);
     defer texbind.unbind();
-    gl.c.glTexParameteri(gl.c.GL_TEXTURE_2D, gl.c.GL_TEXTURE_WRAP_S, gl.c.GL_REPEAT);
+    try texbind.parameter(gl.c.GL_TEXTURE_WRAP_S, gl.c.GL_REPEAT);
-    gl.c.glTexParameteri(gl.c.GL_TEXTURE_2D, gl.c.GL_TEXTURE_WRAP_T, gl.c.GL_REPEAT);
+    try texbind.parameter(gl.c.GL_TEXTURE_WRAP_T, gl.c.GL_REPEAT);
-    gl.c.glTexParameteri(gl.c.GL_TEXTURE_2D, gl.c.GL_TEXTURE_MIN_FILTER, gl.c.GL_LINEAR);
+    try texbind.parameter(gl.c.GL_TEXTURE_MIN_FILTER, gl.c.GL_LINEAR);
-    gl.c.glTexParameteri(gl.c.GL_TEXTURE_2D, gl.c.GL_TEXTURE_MAG_FILTER, gl.c.GL_LINEAR);
+    try texbind.parameter(gl.c.GL_TEXTURE_MAG_FILTER, gl.c.GL_LINEAR);
-    gl.c.glTexImage2D(
+    try texbind.image2D(
-        gl.c.GL_TEXTURE_2D,
         0,
         gl.c.GL_RGB,
         imgwidth,
@@ -61,7 +60,7 @@ pub fn main() !void {
         gl.c.GL_UNSIGNED_BYTE,
         data,
     );
-    gl.c.glGenerateMipmap(gl.c.GL_TEXTURE_2D);
+    texbind.generateMipmap();
 
     // Create our vertex shader
     const vs = try gl.Shader.create(gl.c.GL_VERTEX_SHADER);

src/opengl/Texture.zig

@@ -13,6 +13,41 @@ pub const Binding = struct {
         c.glBindTexture(b.target, 0);
         b.* = undefined;
     }
+
+    pub fn generateMipmap(b: Binding) void {
+        c.glGenerateMipmap(b.target);
+    }
+
+    pub fn parameter(b: Binding, name: c.GLenum, value: anytype) !void {
+        switch (@TypeOf(value)) {
+            c.GLint => c.glTexParameteri(b.target, name, value),
+            else => unreachable,
+        }
+    }
+
+    pub fn image2D(
+        b: Binding,
+        level: c.GLint,
+        internal_format: c.GLint,
+        width: c.GLsizei,
+        height: c.GLsizei,
+        border: c.GLint,
+        format: c.GLenum,
+        typ: c.GLenum,
+        data: *const anyopaque,
+    ) !void {
+        c.glTexImage2D(
+            b.target,
+            level,
+            internal_format,
+            width,
+            height,
+            border,
+            format,
+            typ,
+            data,
+        );
+    }
 };
 
 /// Create a single texture.

src/opengl/draw.zig

@@ -13,3 +13,7 @@ pub fn drawArrays(mode: c.GLenum, first: c.GLint, count: c.GLsizei) !void {
     c.glDrawArrays(mode, first, count);
     try errors.getError();
 }
+
+pub fn viewport(x: c.GLint, y: c.GLint, width: c.GLsizei, height: c.GLsizei) !void {
+    c.glViewport(x, y, width, height);
+}