Fancy metaprogramming for shader uniforms

8 files changed, 413 insertions, 154 deletions

diff --git a/src/fragment.glsl b/src/fragment.glsl
new file mode 100644
index 0000000..1aa44f8
--- /dev/null
+++ b/src/fragment.glsl
@@ -0,0 +1,8 @@
+#version 300 es
+precision highp float;
+
+out vec4 outColor;
+
+void main() {
+    outColor = vec4(1, 0, 0, 1);  // red
+}
diff --git a/src/matrix.zig b/src/matrix.zig
new file mode 100644
index 0000000..025af7c
--- /dev/null
+++ b/src/matrix.zig
@@ -0,0 +1,80 @@
+pub fn Matrix(comptime T: type, rows: usize, cols: usize) type {
+    const RowVec = @Vector(rows, T);
+    const ColVec = @Vector(cols, T);
+
+    return struct {
+        pub const RowT = [rows]T;
+        const Self = @This();
+
+        pub const identity: Self = blk: {
+            const fill = if (T == bool) true else 1;
+            const empty = if (T == bool) false else 0;
+            var r: [cols]@Vector(rows, T) = undefined;
+            for (0..cols) |c| {
+                var irow: RowT = [1]T{empty} ** rows;
+                irow[c] = fill;
+                r[c] = irow;
+            }
+            break :blk .{ .data = r };
+        };
+
+        data: [cols]RowT,
+
+        pub fn multiply(a: Self, b: Self) Self {
+            comptime assert(rows == cols);
+            var result: Self = undefined;
+            for (0..rows) |ri| {
+                const r = a.row(ri);
+                for (0..cols) |ci| {
+                    const c = b.data[ci];
+                    result.data[ci][ri] = @reduce(.Add, r * c);
+                }
+            }
+            return result;
+        }
+
+        pub fn translation(t: @Vector(cols - 1, T)) Self {
+            var base = Self.identity;
+            for (0..cols - 1) |ci| {
+                base.data[ci][rows - 1] = t[ci];
+            }
+            return base;
+        }
+
+        pub fn rotation(angle: T) Self {
+            if (rows < 2 or cols < 2) @compileError("Called rotation on a Matrix smaller than 2x2");
+            const c = @cos(angle);
+            const s = @sin(angle);
+            var base = Self.identity;
+            base.data[0][0] = c;
+            base.data[0][1] = -s;
+            base.data[1][0] = s;
+            base.data[1][1] = c;
+            return base;
+        }
+
+        pub fn scale(sx: T, sy: T) Self {
+            var r = identity;
+            r.data[0][0] = sx;
+            r.data[1][1] = sy;
+            return r;
+        }
+
+        pub fn row(self: Self, ri: usize) RowVec {
+            var r: RowVec = undefined;
+            for (0..cols) |ci| {
+                r[ci] = self.data[ci][ri];
+            }
+            return r;
+        }
+
+        pub fn col(self: Self, ci: usize) ColVec {
+            const start = ci * rows;
+            return self.data[start .. start + cols];
+        }
+    };
+}
+
+fn assert(ok: bool) void {
+    if (!ok) unreachable;
+}
diff --git a/src/vertex.glsl b/src/vertex.glsl
new file mode 100644
index 0000000..cf72553
--- /dev/null
+++ b/src/vertex.glsl
@@ -0,0 +1,8 @@
+#version 300 es
+
+uniform vec2 pos;
+
+void main() {
+    gl_Position = vec4(pos, 0, 1);  // center
+    gl_PointSize = 120.0;
+}
diff --git a/src/wasm.zig b/src/wasm.zig
new file mode 100644
index 0000000..bbea2db
--- /dev/null
+++ b/src/wasm.zig
@@ -0,0 +1,13 @@
+//! The zig interface for accessing functions from the web/javascript
+//! side of the engine. Whenever the engine has a more concrete identity,
+//! this should probably get a more expressive filename.
+
+const std = @import("std");
+
+extern fn consoleLog(ptr: [*c]const u8, len: u32) void;
+
+pub fn print(comptime fmt: []const u8, args: anytype) void {
+    var buf: [512]u8 = undefined;
+    const msg = std.fmt.bufPrint(&buf, fmt, args) catch "There was an error formatting your output string";
+    consoleLog(msg.ptr, msg.len);
+}
diff --git a/src/wasm_msponge.zig b/src/wasm_msponge.zig
index 376e011..8d43fe7 100644
--- a/src/wasm_msponge.zig
+++ b/src/wasm_msponge.zig
@@ -1,10 +1,21 @@
-extern fn consoleLog(ptr: [*c]const u8, len: u32) void;
+const wasm = @import("wasm.zig");
+const webgl = @import("webgl.zig");
+
+const MyProgram = webgl.Program(&.{.{ .identifier = "pos", .shader_name = "pos", .kind = .vec2 }});
+var prog: MyProgram = undefined;
 
 export fn init() void {
-    const message = "Hello Menger Sponge!";
-    consoleLog(message.ptr, message.len);
+    wasm.print("Hello Menger Sponge {d}!", .{2});
+    prog = MyProgram.init(@embedFile("vertex.glsl"), @embedFile("fragment.glsl")) catch return;
 }
 
 export fn update(delta_time: f32) void {
     _ = delta_time;
+    const bg = webgl.Color.fromVec(.{ 1, 0, 1, 1 });
+    webgl.viewportToScreen();
+    webgl.clear(bg);
+
+    prog.use();
+    prog.setUniform(.pos, .{ 0.5, 0.5 });
+    webgl.drawArrays(.points, 0, 1);
 }
diff --git a/src/webgl.js b/src/webgl.js
index 7c60142..823ec53 100644
--- a/src/webgl.js
+++ b/src/webgl.js
@@ -143,7 +143,6 @@ const linkProgram = (program) => {
 
 const shaderSource = (shader, ptr, len) => {
     const source = readString(ptr, len);
-    console.log(source);
     gfx_ctx.shaderSource(glShaders.get(shader), source);
 };
 
diff --git a/src/webgl.zig b/src/webgl.zig
index b97c8fa..145abbd 100644
--- a/src/webgl.zig
+++ b/src/webgl.zig
@@ -1,155 +1,139 @@
-pub const Buffer = extern struct { handle: u32 };
-pub const Shader = packed struct(u32) { handle: u32 };
-pub const Program = packed struct(u32) { handle: u32 };
-pub const Texture = packed struct(u32) { handle: u32 };
-
-pub const GLProgramInfo = enum(u32) {
-    delete_status = 0x8B80,
-    link_status = 0x8B82,
+const std = @import("std");
+const wasm = @import("wasm.zig");
+const bindings = @import("webgl_bindings.zig");
+
+pub const Color = struct {
+    r: f32 = 0,
+    g: f32 = 0,
+    b: f32 = 0,
+    a: f32 = 1,
+
+    pub const red: Color = Color.fromVec(.{ 1, 0, 0, 1 });
+
+    pub fn fromVec(val: @Vector(4, f32)) Color {
+        return .{
+            .r = val[0],
+            .g = val[1],
+            .b = val[2],
+            .a = val[3],
+        };
+    }
 };
 
-pub const GLShaderType = enum(u32) {
-    fragment_shader = 0x8B30,
-    vertex_shader = 0x8B31,
-};
-
-pub const GLShaderInfo = enum(u32) {
-    shader_type = 0x8B4F,
-    delete_status = 0x8B80,
-    compile_status = 0x8B81,
-};
-
-pub const GLBindingPoint = enum(u32) {
-    array_buffer = 0x8892,
-    element_array_buffer = 0x8893,
-};
-
-pub const GLUsagePattern = enum(u32) {
-    stream_draw = 0x88E0,
-    static_draw = 0x88E4,
-    dynamic_draw = 0x88E8,
-};
-
-pub const color_buffer_bit = 0x00004000;
-pub const depth_buffer_bit = 0x00000100;
-
-pub extern fn clearColor(r: f32, g: f32, b: f32, a: f32) void;
-pub extern fn clear(mask: u32) void;
-
-pub extern fn enable(cap: u32) void;
-pub extern fn blendFunc(sfactor: u32, dfactor: u32) void;
-
-pub extern fn createBuffer() Buffer;
-pub extern fn bindBuffer(target: GLBindingPoint, buffer: Buffer) void;
-pub extern fn bufferData(
-    target: GLBindingPoint,
-    ptr: [*c]const f32,
-    len: u32,
-    usage: GLUsagePattern,
-) void;
-
-pub extern fn createShader(shader_type: GLShaderType) Shader;
-pub extern fn shaderSource(shader: Shader, source_ptr: [*c]const u8, len: u32) void;
-pub extern fn compileShader(shader: Shader) void;
-pub extern fn getShaderParameter(shader: Shader, info: GLShaderInfo) u32;
-pub extern fn deleteShader(shader: Shader) void;
-pub extern fn getShaderInfoLog(shader: Shader, buf: [*c]u8, len: u32) u32;
-
-pub extern fn createProgram() Program;
-pub extern fn deleteProgram(program: Program) void;
-pub extern fn attachShader(program: Program, shader: Shader) void;
-pub extern fn linkProgram(program: Program) void;
-pub extern fn getProgramParameter(program: Program, info: GLProgramInfo) u32;
-pub extern fn getProgramInfoLog(program: Program, buf: [*c]const u8, len: u32) u32;
-pub extern fn useProgram(program: Program) void;
-
-pub extern fn getAttribLocation(program: Program, buf: [*c]const u8, len: u32) i32;
-pub extern fn getUniformLocation(program: Program, buf: [*c]const u8, len: u32) i32;
-
-pub extern fn uniform1i(location: i32, v0: i32) void;
-pub extern fn uniform2f(location: i32, v0: f32, v1: f32) void;
-pub extern fn uniform4f(location: i32, v0: f32, v1: f32, v2: f32, v3: f32) void;
-pub extern fn uniformMatrix3fv(location: i32, ptr: [*c]const @Vector(3, f32)) void;
-
-pub const VertexArrayObject = packed struct(u32) { handle: u32 };
-const GLType = enum(u32) {
-    i8 = 0x1400,
-    u8 = 0x1401,
-    i16 = 0x1402,
-    u16 = 0x1403,
-    i32 = 0x1404,
-    u32 = 0x1405,
-    f32 = 0x1406,
-};
+//pub const Program = packed struct(u32) { handle: u32 };
 
-const GLBool = enum(i32) {
-    false = 0,
-    true = 1,
+const UniformInfo = struct {
+    identifier: [:0]const u8,
+    shader_name: []const u8,
+    kind: enum { vec2 },
 };
 
-pub extern fn createVertexArray() VertexArrayObject;
-pub extern fn bindVertexArray(vao: VertexArrayObject) void;
-pub extern fn enableVertexAttribArray(attrib_location: i32) void;
-pub extern fn vertexAttribPointer(
-    attrib_location: u32,
-    size: i32,
-    gl_type: GLType,
-    normalize: GLBool,
-    stride: i32,
-    offset: i32,
-) void;
-
-pub extern fn viewport(x: i32, y: i32, width: i32, height: i32) void;
-
-const GLDrawMode = enum(u32) {
-    points = 0x0000,
-    lines = 0x0001,
-    line_loop = 0x0002,
-    line_strip = 0x0003,
-    triangles = 0x0004,
-    triangle_strip = 0x00005,
-    triangle_fan = 0x00006,
-};
-
-pub extern fn drawArrays(mode: GLDrawMode, first: i32, count: i32) void;
-
-pub extern fn createTexture() Texture;
-
-const TextureBindTarget = enum(u32) {
-    texture_2d = 0x0DE1,
-    texture_cube_map = 0x8514,
-    texture_3d = 0x806F,
-    texture_2d_array = 0x8C1A,
-};
-pub extern fn bindTexture(target: TextureBindTarget, texture: Texture) void;
-
-pub const texture_0 = 0x84c0;
-pub extern fn activeTexture(idx: u32) void;
-
-const TextureTarget = enum(u32) {
-    texture_2d = 0x0DE1,
-};
-const TextureFormat = enum(u32) {
-    rgba = 0x1908,
-};
-pub extern fn texImage2D(
-    target: TextureTarget,
-    level: i32,
-    internal_format: TextureFormat,
-    width: i32,
-    height: i32,
-    border: i32,
-    format: TextureFormat,
-    data_type: GLType,
-    ptr: *const anyopaque,
-    count: u32,
-    offset: u32,
-) void;
-
-pub extern fn vertexAttribDivisor(loc: i32, divisor: i32) void;
-pub extern fn drawArraysInstanced(
-    mode: GLDrawMode,
-    first: i32,
-    count: i32,
-    instace_count: i32,
-) void;
+pub fn Program(comptime uniforms: []const UniformInfo) type {
+    const UniEnum: type = blk: {
+        const EnumField = std.builtin.Type.EnumField;
+        var fields: []const EnumField = &.{};
+        for (uniforms, 0..) |u, i| {
+            const field: EnumField = .{ .name = u.identifier, .value = i };
+            fields = &(fields[0..i].* ++ [1]EnumField{field});
+        }
+
+        const info: std.builtin.Type.Enum = .{
+            .fields = fields,
+            .decls = &.{},
+            .is_exhaustive = false,
+            .tag_type = u32,
+        };
+        break :blk @Type(.{ .Enum = info });
+    };
+    return struct {
+        handle: u32,
+        uniform_handles: [uniforms.len]i32,
+
+        const Self = @This();
+        pub fn init(vert_src: []const u8, frag_src: []const u8) !Self {
+            const vert = try loadShader(.vertex, vert_src);
+            errdefer bindings.deleteShader(vert);
+            const frag = try loadShader(.fragment, frag_src);
+            errdefer bindings.deleteShader(frag);
+
+            const handle = try createProgram(vert, frag);
+
+            var uniform_handles: [uniforms.len]i32 = undefined;
+            for (uniforms, 0..) |u, i| {
+                const h = bindings.getUniformLocation(handle, u.shader_name.ptr, u.shader_name.len);
+                if (h < 0) return error.FailedToGetUniformLocation;
+                uniform_handles[i] = h;
+            }
+
+            return .{ .handle = handle, .uniform_handles = uniform_handles };
+        }
+
+        pub fn use(self: Self) void {
+            bindings.useProgram(self.handle);
+        }
+
+        pub fn setUniform(self: Self, comptime uniform: UniEnum, val: anytype) void {
+            const handle = self.uniform_handles[@intFromEnum(uniform)];
+            const info = uniforms[@intFromEnum(uniform)];
+
+            switch (info.kind) {
+                .vec2 => {
+                    bindings.uniform2f(handle, val[0], val[1]);
+                },
+            }
+        }
+    };
+}
+
+pub fn clear(col: Color) void {
+    bindings.clearColor(col.r, col.g, col.b, col.a);
+    bindings.clear(bindings.color_buffer_bit);
+}
+
+pub fn getScreenSize() [2]f32 {
+    return .{ bindings.getScreenWidth(), bindings.getScreenHeight() };
+}
+
+pub const viewport = bindings.viewport;
+pub fn viewportToScreen() void {
+    const dims = getScreenSize();
+    viewport(0, 0, @intFromFloat(dims[0]), @intFromFloat(dims[1]));
+}
+
+pub const drawArrays = bindings.drawArrays;
+
+fn loadShader(shader_type: bindings.ShaderType, source: []const u8) !u32 {
+    const shader = bindings.createShader(shader_type);
+    errdefer bindings.deleteShader(shader);
+
+    bindings.shaderSource(shader, source.ptr, source.len);
+    bindings.compileShader(shader);
+
+    if (bindings.getShaderParameter(shader, .compile_status) == 0) {
+        var buf: [512]u8 = undefined;
+        const len = bindings.getShaderInfoLog(shader, &buf, buf.len);
+        const msg = buf[0..len];
+        wasm.print("{s}", .{msg});
+        return error.CompilationFailed;
+    }
+
+    return shader;
+}
+
+fn createProgram(vert: u32, frag: u32) !u32 {
+    const program = bindings.createProgram();
+    errdefer bindings.deleteProgram(program);
+
+    bindings.attachShader(program, vert);
+    bindings.attachShader(program, frag);
+    bindings.linkProgram(program);
+    if (bindings.getProgramParameter(program, .link_status) == 0) {
+        var buf: [512]u8 = undefined;
+        const len = bindings.getProgramInfoLog(program, &buf, buf.len);
+        const msg = buf[0..len];
+        wasm.print("{s}", .{msg});
+        return error.LinkFailed;
+    }
+
+    return program;
+}
diff --git a/src/webgl_bindings.zig b/src/webgl_bindings.zig
new file mode 100644
index 0000000..b152353
--- /dev/null
+++ b/src/webgl_bindings.zig
@@ -0,0 +1,156 @@
+pub const Buffer = extern struct { handle: u32 };
+pub const Texture = packed struct(u32) { handle: u32 };
+
+pub const GLProgramInfo = enum(u32) {
+    delete_status = 0x8B80,
+    link_status = 0x8B82,
+};
+
+pub const ShaderInfo = enum(u32) {
+    shader_type = 0x8B4F,
+    delete_status = 0x8B80,
+    compile_status = 0x8B81,
+};
+
+pub const GLBindingPoint = enum(u32) {
+    array_buffer = 0x8892,
+    element_array_buffer = 0x8893,
+};
+
+pub const GLUsagePattern = enum(u32) {
+    stream_draw = 0x88E0,
+    static_draw = 0x88E4,
+    dynamic_draw = 0x88E8,
+};
+
+pub const color_buffer_bit = 0x00004000;
+pub const depth_buffer_bit = 0x00000100;
+
+pub extern fn getScreenHeight() f32;
+pub extern fn getScreenWidth() f32;
+
+pub extern fn clearColor(r: f32, g: f32, b: f32, a: f32) void;
+pub extern fn clear(mask: u32) void;
+
+pub extern fn enable(cap: u32) void;
+pub extern fn blendFunc(sfactor: u32, dfactor: u32) void;
+
+pub extern fn createBuffer() Buffer;
+pub extern fn bindBuffer(target: GLBindingPoint, buffer: Buffer) void;
+pub extern fn bufferData(
+    target: GLBindingPoint,
+    ptr: [*c]const f32,
+    len: u32,
+    usage: GLUsagePattern,
+) void;
+
+pub const ShaderType = enum(u32) {
+    fragment = 0x8B30,
+    vertex = 0x8B31,
+};
+
+pub extern fn createShader(shader_type: ShaderType) u32;
+pub extern fn shaderSource(shader: u32, source_ptr: [*c]const u8, len: u32) void;
+pub extern fn compileShader(shader: u32) void;
+pub extern fn getShaderParameter(shader: u32, info: ShaderInfo) u32;
+pub extern fn deleteShader(shader: u32) void;
+pub extern fn getShaderInfoLog(shader: u32, buf: [*c]u8, len: u32) u32;
+
+pub extern fn createProgram() u32;
+pub extern fn deleteProgram(program: u32) void;
+pub extern fn attachShader(program: u32, shader: u32) void;
+pub extern fn linkProgram(program: u32) void;
+pub extern fn getProgramParameter(program: u32, info: GLProgramInfo) u32;
+pub extern fn getProgramInfoLog(program: u32, buf: [*c]const u8, len: u32) u32;
+pub extern fn useProgram(program: u32) void;
+
+pub extern fn getAttribLocation(program: u32, buf: [*c]const u8, len: u32) i32;
+pub extern fn getUniformLocation(program: u32, buf: [*c]const u8, len: u32) i32;
+
+pub extern fn uniform1i(location: i32, v0: i32) void;
+pub extern fn uniform2f(location: i32, v0: f32, v1: f32) void;
+pub extern fn uniform4f(location: i32, v0: f32, v1: f32, v2: f32, v3: f32) void;
+pub extern fn uniformMatrix3fv(location: i32, ptr: [*c]const @Vector(3, f32)) void;
+
+pub const VertexArrayObject = packed struct(u32) { handle: u32 };
+const GLType = enum(u32) {
+    i8 = 0x1400,
+    u8 = 0x1401,
+    i16 = 0x1402,
+    u16 = 0x1403,
+    i32 = 0x1404,
+    u32 = 0x1405,
+    f32 = 0x1406,
+};
+
+const GLBool = enum(i32) {
+    false = 0,
+    true = 1,
+};
+
+pub extern fn createVertexArray() VertexArrayObject;
+pub extern fn bindVertexArray(vao: VertexArrayObject) void;
+pub extern fn enableVertexAttribArray(attrib_location: i32) void;
+pub extern fn vertexAttribPointer(
+    attrib_location: u32,
+    size: i32,
+    gl_type: GLType,
+    normalize: GLBool,
+    stride: i32,
+    offset: i32,
+) void;
+
+pub extern fn viewport(x: i32, y: i32, width: i32, height: i32) void;
+
+const DrawMode = enum(u32) {
+    points = 0x0000,
+    lines = 0x0001,
+    line_loop = 0x0002,
+    line_strip = 0x0003,
+    triangles = 0x0004,
+    triangle_strip = 0x00005,
+    triangle_fan = 0x00006,
+};
+
+pub extern fn drawArrays(mode: DrawMode, first: i32, count: i32) void;
+
+pub extern fn createTexture() Texture;
+
+const TextureBindTarget = enum(u32) {
+    texture_2d = 0x0DE1,
+    texture_cube_map = 0x8514,
+    texture_3d = 0x806F,
+    texture_2d_array = 0x8C1A,
+};
+pub extern fn bindTexture(target: TextureBindTarget, texture: Texture) void;
+
+pub const texture_0 = 0x84c0;
+pub extern fn activeTexture(idx: u32) void;
+
+const TextureTarget = enum(u32) {
+    texture_2d = 0x0DE1,
+};
+const TextureFormat = enum(u32) {
+    rgba = 0x1908,
+};
+pub extern fn texImage2D(
+    target: TextureTarget,
+    level: i32,
+    internal_format: TextureFormat,
+    width: i32,
+    height: i32,
+    border: i32,
+    format: TextureFormat,
+    data_type: GLType,
+    ptr: *const anyopaque,
+    count: u32,
+    offset: u32,
+) void;
+
+pub extern fn vertexAttribDivisor(loc: i32, divisor: i32) void;
+pub extern fn drawArraysInstanced(
+    mode: DrawMode,
+    first: i32,
+    count: i32,
+    instace_count: i32,
+) void;