Initial support for instanced rendering

[libs/gl.git] / source / vertexsetup.cpp

diff --git a/source/vertexsetup.cpp b/source/vertexsetup.cpp
index 547dc0967584f690e7c29f4e82baf564c32d1838..8465ab060d54fe77041106a2c3c67a342102116e 100644 (file)
--- a/source/vertexsetup.cpp
+++ b/source/vertexsetup.cpp
@@ -1,5 +1,6 @@
 #include <msp/core/raii.h>
 #include <msp/gl/extensions/arb_direct_state_access.h>
+#include <msp/gl/extensions/arb_instanced_arrays.h>
 #include <msp/gl/extensions/arb_vertex_array_object.h>
 #include <msp/gl/extensions/arb_vertex_attrib_binding.h>
 #include <msp/gl/extensions/arb_vertex_buffer_object.h>
@@ -14,7 +15,8 @@ namespace GL {
 
 VertexSetup::VertexSetup():
        dirty(0),
-       array(0),
+       vertex_array(0),
+       inst_array(0),
        index_buffer(0)
 {
        static Require req(ARB_vertex_array_object);
@@ -33,10 +35,19 @@ VertexSetup::~VertexSetup()
 
 void VertexSetup::set_vertex_array(const VertexArray &a)
 {
-       array = &a;
+       vertex_array = &a;
        update(VERTEX_ARRAY);
 }
 
+void VertexSetup::set_instance_array(const VertexArray *a)
+{
+       if(a)
+               static Require req(ARB_instanced_arrays);
+
+       inst_array = a;
+       update(INSTANCE_ARRAY);
+}
+
 void VertexSetup::set_index_buffer(const Buffer &ibuf)
 {
        index_buffer = &ibuf;
@@ -53,7 +64,13 @@ void VertexSetup::update(unsigned mask) const
        }
 
        if(mask&VERTEX_ARRAY)
-               update_vertex_array(direct);
+               update_vertex_array(*vertex_array, 0, 0, direct);
+
+       if(mask&INSTANCE_ARRAY)
+       {
+               if(inst_array)
+                       update_vertex_array(*inst_array, 1, 1, direct);
+       }
 
        if(mask&INDEX_BUFFER)
        {
@@ -64,14 +81,17 @@ void VertexSetup::update(unsigned mask) const
        }
 }
 
-void VertexSetup::update_vertex_array(bool direct) const
+void VertexSetup::update_vertex_array(const VertexArray &array, unsigned binding, unsigned divisor, bool direct) const
 {
-       Conditional<Bind> bind_vbuf(!direct, array->get_buffer(), ARRAY_BUFFER);
+       Conditional<Bind> bind_vbuf(!direct, array.get_buffer(), ARRAY_BUFFER);
 
-       const VertexFormat &fmt = array->get_format();
+       const VertexFormat &fmt = array.get_format();
        unsigned stride = get_stride(fmt)*sizeof(float);
        if(direct)
-               glVertexArrayVertexBuffer(id, 0, array->get_buffer()->get_id(), 0, stride);
+       {
+               glVertexArrayVertexBuffer(id, binding, array.get_buffer()->get_id(), 0, stride);
+               glVertexArrayBindingDivisor(id, binding, divisor);
+       }
 
        unsigned offset = 0;
        for(const unsigned char *c=fmt.begin(); c!=fmt.end(); ++c)
@@ -86,7 +106,7 @@ void VertexSetup::update_vertex_array(bool direct) const
                                glVertexArrayAttribFormat(id, t, 4, GL_UNSIGNED_BYTE, true, offset);
                        else
                                glVertexArrayAttribFormat(id, t, sz, GL_FLOAT, false, offset);
-                       glVertexArrayAttribBinding(id, t, 0);
+                       glVertexArrayAttribBinding(id, t, binding);
                        glEnableVertexArrayAttrib(id, t);
                }
                else
@@ -95,6 +115,7 @@ void VertexSetup::update_vertex_array(bool direct) const
                                glVertexAttribPointer(t, 4, GL_UNSIGNED_BYTE, true, stride, reinterpret_cast<unsigned char *>(offset));
                        else
                                glVertexAttribPointer(t, sz, GL_FLOAT, false, stride, reinterpret_cast<float *>(offset));
+                       glVertexAttribDivisor(t, divisor);
                        glEnableVertexAttribArray(t);
                }
                offset += sz*sizeof(float);