shader: Add more tests

internal/shader/testdata/assign.expected.vs

@@ -0,0 +1,7 @@
+void F0(in vec2 l0, out vec4 l1) {
+	float l2 = 0.0;
+	l2 = 0.000000000e+00;
+	l2 = (l2) + (1.000000000e+00);
+	l1 = vec4(l0, l2, l2);
+	return;
+}

internal/shader/testdata/assign.go

@@ -0,0 +1,8 @@
+package main
+
+func Foo(foo vec2) vec4 {
+	var r1 float
+	r1 = 0.0
+	r1 += 1.0
+	return vec4(foo, r1, r1)
+}

internal/shader/testdata/assign_multiple.expected.vs

@@ -6,7 +6,7 @@ void F0(in vec2 l0, out vec4 l1) {
 	F1(l4, l5);
 	l2 = l4;
 	l3 = l5;
-	l1 = vec4(l0, l2, l2);
+	l1 = vec4(l0, l2, l3);
 	return;
 }
 

internal/shader/testdata/assign_multiple.go

@@ -3,7 +3,7 @@ package main
 func Foo(foo vec2) vec4 {
 	var r1, r2 float
 	r1, r2 = Bar()
-	return vec4(foo, r1, r1)
+	return vec4(foo, r1, r2)
 }
 
 func Bar() (float, float) {

internal/shader/testdata/define_type.expected.vs

@@ -0,0 +1,6 @@
+void F0(in vec2 l0, out vec4 l1) {
+	vec4 l2 = vec4(0.0);
+	l2 = (vec4(0.000000000e+00)) * (vec4(0.000000000e+00));
+	l1 = l2;
+	return;
+}

internal/shader/testdata/define_type.go

@@ -0,0 +1,6 @@
+package main
+
+func Foo(foo vec2) vec4 {
+	r := vec4(0.0) * vec4(0.0)
+	return r
+}