Support user clip planes in generated shaders

diff --git a/source/programbuilder.cpp b/source/programbuilder.cpp
index e1b34d0906aa3c7c02367e92982d353df2c908a3..f8c3973f8b8feba30da190196a588d7a62b711ca 100644 (file)
--- a/source/programbuilder.cpp
+++ b/source/programbuilder.cpp
@@ -110,6 +110,7 @@ const ProgramBuilder::VariableDefinition ProgramBuilder::standard_variables[] =
        { FRAGMENT, "diffuse_sample", "vec4", "texture2D(diffusemap, texture_coord)", 0 },
 
        { VERTEX, "gl_Position", "vec4", "projection_matrix*eye_vertex", 0 },
+       { VERTEX, "gl_ClipDistance[i]", "float", "dot(eye_vertex, clip_planes[i].equation)", "c" },
        { VERTEX, "fog_coord", "float", "-eye_vertex.z", 0 },
        { VERTEX, "shd_vertex", "vec3", "(shd_eye_matrix*eye_vertex).xyz", 0 },
        { VERTEX, "tbn_sky_dir", "vec3", "eye_sky_dir*eye_tbn_matrix", "n" },
@@ -151,9 +152,11 @@ const ProgramBuilder::VariableDefinition ProgramBuilder::standard_variables[] =
        { UNIFORM, "Lighting::fog_color", "vec4", "gl_Fog.color", 0 },
        { UNIFORM, "Lighting::fog_density", "float", "gl_Fog.density", 0 },
        { UNIFORM, "Material::material", "MaterialParameters", "gl_FrontMaterial", 0 },
+       { UNIFORM, "Clipping::clip_planes", "ClipPlane[MAX_CLIP_PLANES]", 0, 0 },
 
        { TYPE, "LightSourceParameters", "struct { vec4 position; vec4 diffuse; vec4 specular; }", "gl_LightSourceParameters", 0 },
        { TYPE, "MaterialParameters", "struct { vec4 ambient; vec4 diffuse; vec4 specular; float shininess; }", "gl_MaterialParameters", 0 },
+       { TYPE, "ClipPlane", "struct { vec4 equation; }", 0, 0 },
 
        // Terminator entry
        { NO_SCOPE, 0, 0, 0, 0 }
@@ -272,6 +275,8 @@ void ProgramBuilder::add_shaders(Program &prog) const
        list<ShaderVariable> variables;
        list<ShaderVariable *> resolved_vars;
 
+       if(features.clipping)
+               variables.push_back(ShaderVariable("gl_ClipDistance[i]"));
        variables.push_front(ShaderVariable("gl_Position"));
        variables.push_front(ShaderVariable(features.legacy ? "gl_FragColor" : "frag_color"));
 
@@ -454,6 +459,10 @@ string ProgramBuilder::create_source(const list<ShaderVariable *> &variables, Va
                }
        }
 
+       // The clip distance array must be declared manually to give it a size
+       if(scope==VERTEX && features.clipping)
+               source += format("out float gl_ClipDistance[%d];\n", features.max_clip_planes);
+
        source += "void main()\n{\n";
 
        list<ShaderVariable *> loop_vars;
@@ -490,7 +499,7 @@ string ProgramBuilder::create_source(const list<ShaderVariable *> &variables, Va
                                }
 
                                InterfaceFlags iface = (*j)->get_interface_flags(scope);
-                               if(iface&OUTPUT)
+                               if((iface&(OUTPUT|GOAL))==OUTPUT)
                                {
                                        string expr = ((*j)->inlined ? create_expression(**j, "i") : (*j)->resolved_name+"[i]");
                                        source += format("\t\t%c_%s[i] = %s;\n", interfaces[scope], (*j)->resolved_name, expr);
@@ -503,7 +512,7 @@ string ProgramBuilder::create_source(const list<ShaderVariable *> &variables, Va
 
                InterfaceFlags iface = (*i)->get_interface_flags(scope);
 
-               if((*i)->array_size>1)
+               if((*i)->array_size>1 || ((*i)->array_size==1 && (iface&GOAL)))
                {
                        if((*i)->variable->scope==scope || (iface&OUTPUT))
                        {
@@ -731,7 +740,9 @@ ProgramBuilder::StandardFeatures::StandardFeatures():
        specular(false),
        normalmap(false),
        shadow(false),
-       reflection(false)
+       reflection(false),
+       clipping(false),
+       max_clip_planes(1)
 {
        if(get_gl_api()==OPENGL_ES2)
                legacy = !(get_glsl_version()>=Version(3, 0));
@@ -762,6 +773,8 @@ string ProgramBuilder::StandardFeatures::create_flags() const
                flags += 's';
        if(reflection)
                flags += 'e';
+       if(clipping)
+               flags += 'c';
        if(legacy && get_gl_api()==OPENGL)
                flags += 'g';
 
@@ -861,6 +874,8 @@ void ProgramBuilder::ShaderVariable::resolve_array(const StandardFeatures &featu
        {
                if(array_subscript=="MAX_LIGHTS")
                        array_size = features.max_lights;
+               else if(array_subscript=="MAX_CLIP_PLANES")
+                       array_size = features.max_clip_planes;
                else if(isnumrc(array_subscript))
                        array_size = lexical_cast<unsigned>(array_subscript);
                else

diff --git a/source/programbuilder.h b/source/programbuilder.h
index ecd006d552709eec6656a3409efe47b5bb6afa51..97a706e077d93d3729c65eba5290c5a6a5b285e2 100644 (file)
--- a/source/programbuilder.h
+++ b/source/programbuilder.h
@@ -98,6 +98,12 @@ public:
                equivalend in the pipeline. */
                bool reflection;
 
+               /** Clip primitives against user defined clip planes. */
+               bool clipping;
+
+               /** Number of clipping planes to process. */
+               unsigned max_clip_planes;
+
                /** Force the use of legacy shaders conforming to GLSL 1.10.   Defaults
                to true if the version of GLSL is less than 1.30, false otherwise. */
                bool legacy;