first commit

src/gl_helper/model.zig

@@ -0,0 +1,44 @@
+const std = @import("std");
+const ArrayList = std.ArrayList;
+
+const zm = @import("zmath");
+
+const Mesh = @import("mesh.zig");
+const Shader = @import("shader.zig");
+const Tree = @import("../tree.zig").Tree;
+
+pub const JointData = struct {
+    mesh: Mesh,
+    translation: zm.Mat,
+    rotation: zm.Quat,
+};
+
+data: Tree(JointData),
+
+pub fn init(
+    data: Tree(JointData),
+) @This() {
+    return .{ .data = data };
+}
+
+pub fn draw(self: *@This(), shader: Shader) void {
+    var iter = self.data.depthFirstIterator();
+    while (iter.next()) |node| {
+        var rotation = node.val.rotation;
+        var current = node;
+        while (current.parent) |parent| {
+            rotation = zm.qmul(rotation, parent.val.rotation);
+            current = parent;
+        }
+
+        const model_matrix = zm.mul(zm.quatToMat(rotation), node.val.translation);
+        const normal_matrix = zm.transpose(zm.inverse(model_matrix));
+        shader.updateUniformMatrix("u_model_matrix", &.{model_matrix});
+        shader.updateUniformMatrix("u_normal_matrix", &.{normal_matrix});
+        node.val.mesh.draw(shader);
+    }
+}
+
+pub fn deinit(self: *@This(), allocator: std.mem.Allocator) void {
+    self.data.deinit(allocator);
+}