vkd3d-shader/hlsl: Add support for fmod() intrinsic.

Approved-by: Giovanni Mascellani (@giomasce)
Approved-by: Zebediah Figura (@zfigura)
Approved-by: Henri Verbeet (@hverbeet)
Approved-by: Alexandre Julliard (@julliard)
Merge-Request: https://gitlab.winehq.org/wine/vkd3d/-/merge_requests/195

Makefile.am

@@ -71,6 +71,7 @@ vkd3d_shader_tests = \
 	tests/exp.shader_test \
 	tests/expr-indexing.shader_test \
 	tests/floor.shader_test \
+	tests/fmod.shader_test \
 	tests/frac.shader_test \
 	tests/function-return.shader_test \
 	tests/hlsl-array-dimension.shader_test \

libs/vkd3d-shader/hlsl.y

@@ -2697,6 +2697,49 @@ static bool intrinsic_floor(struct hlsl_ctx *ctx,
     return !!add_unary_arithmetic_expr(ctx, params->instrs, HLSL_OP1_FLOOR, arg, loc);
 }
 
+static bool intrinsic_fmod(struct hlsl_ctx *ctx, const struct parse_initializer *params,
+        const struct vkd3d_shader_location *loc)
+{
+    struct hlsl_ir_node *x, *y, *div, *abs, *frac, *neg_frac, *ge;
+    struct hlsl_ir_constant *zero;
+    struct hlsl_ir_load *select;
+    unsigned int count, i;
+
+    if (!(x = intrinsic_float_convert_arg(ctx, params, params->args[0], loc)))
+        return false;
+
+    if (!(y = intrinsic_float_convert_arg(ctx, params, params->args[1], loc)))
+        return false;
+
+    if (!(div = add_binary_arithmetic_expr(ctx, params->instrs, HLSL_OP2_DIV, x, y, loc)))
+        return false;
+
+    if (!(zero = hlsl_new_constant(ctx, div->data_type, loc)))
+        return false;
+    list_add_tail(params->instrs, &zero->node.entry);
+
+    count = hlsl_type_element_count(div->data_type);
+    for (i = 0; i < count; ++i)
+        zero->value.u[i].f = 0.0f;
+
+    if (!(abs = add_unary_arithmetic_expr(ctx, params->instrs, HLSL_OP1_ABS, div, loc)))
+        return false;
+
+    if (!(frac = add_unary_arithmetic_expr(ctx, params->instrs, HLSL_OP1_FRACT, abs, loc)))
+        return false;
+
+    if (!(neg_frac = add_unary_arithmetic_expr(ctx, params->instrs, HLSL_OP1_NEG, frac, loc)))
+        return false;
+
+    if (!(ge = add_binary_comparison_expr(ctx, params->instrs, HLSL_OP2_GEQUAL, div, &zero->node, loc)))
+        return false;
+
+    if (!(select = hlsl_add_conditional(ctx, params->instrs, ge, frac, neg_frac)))
+        return false;
+
+    return !!add_binary_arithmetic_expr(ctx, params->instrs, HLSL_OP2_MUL, &select->node, y, loc);
+}
+
 static bool intrinsic_frac(struct hlsl_ctx *ctx,
         const struct parse_initializer *params, const struct vkd3d_shader_location *loc)
 {
@@ -3456,6 +3499,7 @@ intrinsic_functions[] =
     {"exp",                                 1, true,  intrinsic_exp},
     {"exp2",                                1, true,  intrinsic_exp2},
     {"floor",                               1, true,  intrinsic_floor},
+    {"fmod",                                2, true,  intrinsic_fmod},
     {"frac",                                1, true,  intrinsic_frac},
     {"ldexp",                               2, true,  intrinsic_ldexp},
     {"length",                              1, true,  intrinsic_length},

tests/fmod.shader_test

@@ -0,0 +1,13 @@
+[pixel shader]
+float4 main(uniform float4 u) : sv_target
+{
+    return float4(fmod(u.x, u.y), 0, 0, 0);
+}
+
+[test]
+uniform 0 float4 -0.5 6.5 0.0 0.0
+draw quad
+probe all rgba (-0.5, 0.0, 0.0, 0.0) 4
+uniform 0 float4 1.1 0.3 0.0 0.0
+draw quad
+probe all rgba (0.2, 0.0, 0.0, 0.0) 4