tutorial: make the FBO example display something at last, so we can port

it to DirectX.

tutorial/08_fbo.cpp

@@ -14,6 +14,7 @@
 
 #include "core.h"
 #include "loldebug.h"
+#include "lolgl.h"
 
 using namespace std;
 using namespace lol;
@@ -29,12 +30,28 @@ class FBO : public WorldEntity
 public:
     FBO()
     {
-        m_vertices << vec2( 0.0,  0.8);
-        m_vertices << vec2(-0.8, -0.8);
-        m_vertices << vec2( 0.8, -0.8);
+        m_vertices << vec2( 1.0,  1.0);
+        m_vertices << vec2(-1.0, -1.0);
+        m_vertices << vec2( 1.0, -1.0);
+        m_vertices << vec2(-1.0, -1.0);
+        m_vertices << vec2( 1.0,  1.0);
+        m_vertices << vec2(-1.0,  1.0);
         m_ready = false;
     }
 
+    virtual void TickGame(float seconds)
+    {
+        WorldEntity::TickGame(seconds);
+
+        m_time += seconds;
+        m_hotspot = 0.4f * vec3(lol::cos(m_time * 2.f) + lol::cos(m_time * 3.3f),
+                                lol::sin(m_time * 4.4f) + lol::sin(m_time * 3.2f),
+                                lol::sin(m_time * 5.f));
+        m_color = 0.25f * vec3(3.f + lol::sin(m_time * 4.5f + 1.f),
+                               3.f + lol::sin(m_time * 2.8f + 1.3f),
+                               3.f + lol::sin(m_time * 3.7f));
+    }
+
     virtual void TickDraw(float seconds)
     {
         WorldEntity::TickDraw(seconds);
@@ -43,6 +60,10 @@ public:
         {
             m_shader = Shader::Create(lolfx_08_fbo);
             m_coord = m_shader->GetAttribLocation("in_Position", VertexUsage::Position, 0);
+            m_uni_point = m_shader->GetUniformLocation("in_Point");
+            m_uni_color = m_shader->GetUniformLocation("in_Color");
+            m_uni_flag = m_shader->GetUniformLocation("in_Flag");
+            m_uni_texture = m_shader->GetUniformLocation("in_Texture");
 
             m_vdecl = new VertexDeclaration(VertexStream<vec2>(VertexUsage::Position));
 
@@ -52,6 +73,11 @@ public:
             m_vbo->Unlock();
 
             m_fbo = new FrameBuffer(Video::GetSize());
+            m_fbo->Bind();
+            glClearColor(0.0, 0.0, 0.0, 1.0f);
+            glClearDepth(1.0f);
+            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+            m_fbo->Unbind();
 
             m_ready = true;
 
@@ -59,18 +85,25 @@ public:
         }
 
         m_fbo->Bind();
+        /* FIXME: we should just disable depth test in the shader */
+        glClear(GL_DEPTH_BUFFER_BIT);
         m_shader->Bind();
+        m_shader->SetUniform(m_uni_flag, 0.f);
+        m_shader->SetUniform(m_uni_point, m_hotspot);
+        m_shader->SetUniform(m_uni_color, m_color);
         m_vdecl->SetStream(m_vbo, m_coord);
         m_vdecl->Bind();
-        m_vdecl->DrawElements(MeshPrimitive::Triangles, 0, 1);
+        m_vdecl->DrawElements(MeshPrimitive::Triangles, 0, 2);
         m_vdecl->Unbind();
         m_shader->Unbind();
         m_fbo->Unbind();
 
         m_shader->Bind();
+        m_shader->SetUniform(m_uni_flag, 1.f);
+        m_shader->SetTexture(m_uni_texture, m_fbo->GetTexture(), 0);
         m_vdecl->SetStream(m_vbo, m_coord);
         m_vdecl->Bind();
-        m_vdecl->DrawElements(MeshPrimitive::Triangles, 0, 1);
+        m_vdecl->DrawElements(MeshPrimitive::Triangles, 0, 2);
         m_vdecl->Unbind();
         m_shader->Unbind();
     }
@@ -79,9 +112,12 @@ private:
     Array<vec2> m_vertices;
     Shader *m_shader;
     ShaderAttrib m_coord;
+    ShaderUniform m_uni_flag, m_uni_point, m_uni_color, m_uni_texture;
     VertexDeclaration *m_vdecl;
     VertexBuffer *m_vbo;
     FrameBuffer *m_fbo;
+    double m_time;
+    vec3 m_hotspot, m_color;
     bool m_ready;
 };
 
@@ -95,7 +131,6 @@ int main(int argc, char **argv)
     _chdir("../..");
 #endif
 
-    new DebugFps(5, 5);
     new FBO();
 
     app.Run();

tutorial/08_fbo.lolfx

@@ -2,21 +2,42 @@
 
 #version 120
 
+attribute vec2 in_Position;
+
+varying vec2 pass_Position;
+
 void main()
 {
-    gl_Position = gl_Vertex;
-    gl_TexCoord[0] = gl_MultiTexCoord0;
+    pass_Position = in_Position;
+    gl_Position = vec4(in_Position, 0.0, 1.0);
 }
 
 -- GLSL.Frag --
 
 #version 120
 
-uniform sampler2D texture;
+uniform sampler2D in_Texture;
+uniform float in_Flag;
+uniform vec3 in_Point;
+uniform vec3 in_Color;
+
+varying vec2 pass_Position;
 
 void main(void)
 {
-    gl_FragColor = vec4(texture2D(texture, gl_TexCoord[0].xy).xyz, 1.0);
+    if (in_Flag == 0.0)
+    {
+        float s = 4.0 + 4.0 * in_Point.z;
+        vec2 p = pass_Position - in_Point.xy * 0.8;
+        float f = clamp(1.0 - dot(s * p, s * p), 0.0, 1.0);
+        f = sqrt(f);
+        gl_FragColor = vec4(f * in_Color, f + 0.1);
+    }
+    else
+    {
+        vec2 texcoords = pass_Position * 0.5 + vec2(0.5, 0.5);
+        gl_FragColor = vec4(texture2D(in_Texture, texcoords).xyz, 1.0);
+    }
 }
 
 -- HLSL.Vert --