CPVRTPrint3D made rotating content disappear

[renaissance]

My application is very similar to the TrainingCourse5_BasicTnL in the PC version (OGLES2_WINDOWS_PCEMULATION_2.06.26.0649) . The only difference is I would like add text to the window.  After I compiled the code and run it, the very first frame is exactly what I am looking for, with the text and the target.

When I use the PVRVFRAME to start the rotation, the triangle is gone.

I am wondering what caused this problem.  Thank you very much.

In the following is the source code of the OGLES2BasicTnL.cpp I modified by adding the text in there (highlighted with red color).

 

/******************************************************************************

 @File         OGLES2BasicTnL.cpp

 @Title        Shows basic transformations and lighting

 @Version     

 @Copyright    Copyright (C)  Imagination Technologies Limited.

 @Platform     Independant

 @Description  Shows basic transformations and lighting

******************************************************************************/
#include <math.h>
#include <stdio.h>

#if defined(__APPLE__)
#import <OpenGLES/ES2/gl.h>
#import <OpenGLES/ES2/glext.h>
#else
#include <EGL/egl.h>
#include <GLES2/gl2.h>
#endif

#include "PVRShell.h"
#include "OGLES2Tools.h" 

/******************************************************************************
 Defines
******************************************************************************/

// Index to bind the attributes to vertex shaders
#define VERTEX_ARRAY 0
#define TEXCOORD_ARRAY 1
#define NORMAL_ARRAY 2

// Size of the texture we create
#define TEX_SIZE  128

/*!****************************************************************************
 Class implementing the PVRShell functions.
******************************************************************************/
class OGLESBasicTnL : public PVRShell
{
 // The vertex and fragment shader OpenGL handles
 GLuint m_uiVertexShader, m_uiFragShader;

 // The program object containing the 2 shader objects
 GLuint m_uiProgramObject;

 // Texture handle
 GLuint m_uiTexture;

 // VBO handle
 GLuint m_ui32Vbo;

 //
 unsigned int m_ui32VertexStride;

 // Angle to rotate the triangle
 float m_fAngle;
 
 // Print3D class used to display text
 CPVRTPrint3D m_Print3D;

public:
 virtual bool InitApplication();
 virtual bool InitView();
 virtual bool ReleaseView();
 virtual bool QuitApplication();
 virtual bool RenderScene();
};

/*!****************************************************************************
 @Function  InitApplication
 @Return  bool  true if no error occured
 @Description Code in InitApplication() will be called by PVRShell once per
    run, before the rendering context is created.
    Used to initialize variables that are not dependant on it
    (e.g. external modules, loading meshes, etc.)
    If the rendering context is lost, InitApplication() will
    not be called again.
******************************************************************************/
bool OGLESBasicTnL::InitApplication()
{
 m_fAngle = 0;
 return true;
}

/*!****************************************************************************
 @Function  QuitApplication
 @Return  bool  true if no error occured
 @Description Code in QuitApplication() will be called by PVRShell once per
    run, just before exiting the program.
    If the rendering context is lost, QuitApplication() will
    not be called.
******************************************************************************/
bool OGLESBasicTnL::QuitApplication()
{
    return true;
}

/*!****************************************************************************
 @Function  InitView
 @Return  bool  true if no error occured
 @Description Code in InitView() will be called by PVRShell upon
    initialization or after a change in the rendering context.
    Used to initialize variables that are dependant on the rendering
    context (e.g. textures, vertex buffers, etc.)
******************************************************************************/
bool OGLESBasicTnL::InitView()
{
 
 bool bRotate = false;
 if(m_Print3D.SetTextures(0,PVRShellGet(prefWidth),PVRShellGet(prefHeight), bRotate) != PVR_SUCCESS)
 {
  PVRShellSet(prefExitMessage, "ERROR: Cannot initialise Print3Dn");
  return false;
 }  

 // Fragment and vertex shaders code
 char* pszFragShader = "
  uniform sampler2D sampler2d;
  varying mediump float varDot;
  varying mediump vec2 varCoord;
  void main (void)
  {
      gl_FragColor = texture2D(sampler2d,varCoord) * varDot;
  }";

 char* pszVertShader = "
  attribute highp vec4 myVertex;
  attribute mediump vec3 myNormal;
  attribute mediump vec4 myUV;
  uniform mediump mat4 myPMVMatrix;
  uniform mediump mat3 myModelViewIT;
  uniform mediump vec3 myLightDirection;
  varying mediump float varDot;
  varying mediump vec2 varCoord;
  void main(void)
  {
   gl_Position = myPMVMatrix * myVertex;
   varCoord = myUV.st;
   mediump vec3 transNormal = myModelViewIT * myNormal;
   varDot = max( dot(transNormal, myLightDirection), 0.0 );
  }";

 // Create the fragment shader object
 m_uiFragShader = glCreateShader(GL_FRAGMENT_SHADER);

 // Load the source code into it
 glShaderSource(m_uiFragShader, 1, (const char**)&pszFragShader, NULL);

 // Compile the source code
 glCompileShader(m_uiFragShader);

 // Check if compilation succeeded
 GLint bShaderCompiled;
    glGetShaderiv(m_uiFragShader, GL_COMPILE_STATUS, &bShaderCompiled);
 if (!bShaderCompiled)
 {
  // An error happened, first retrieve the length of the log message
  int i32InfoLogLength, i32CharsWritten;
  glGetShaderiv(m_uiFragShader, GL_INFO_LOG_LENGTH, &i32InfoLogLength);

  // Allocate enough space for the message and retrieve it
  char* pszInfoLog = new char[i32InfoLogLength];
        glGetShaderInfoLog(m_uiFragShader, i32InfoLogLength, &i32CharsWritten, pszInfoLog);

  /*
   Displays the message in a dialog box when the application quits
   using the shell PVRShellSet function with first parameter prefExitMessage.
  */
  char* pszMsg = new char[i32InfoLogLength+256];
  sprintf(pszMsg, "Failed to compile fragment shader: %s", pszInfoLog);
  PVRShellSet(prefExitMessage, pszMsg);
  delete [] pszMsg;
  delete [] pszInfoLog;
  return false;
 }

 // Loads the vertex shader in the same way
 m_uiVertexShader = glCreateShader(GL_VERTEX_SHADER);
 glShaderSource(m_uiVertexShader, 1, (const char**)&pszVertShader, NULL);
 glCompileShader(m_uiVertexShader);
    glGetShaderiv(m_uiVertexShader, GL_COMPILE_STATUS, &bShaderCompiled);
 if (!bShaderCompiled)
 {
  int i32InfoLogLength, i32CharsWritten;
  glGetShaderiv(m_uiVertexShader, GL_INFO_LOG_LENGTH, &i32InfoLogLength);
  char* pszInfoLog = new char[i32InfoLogLength];
        glGetShaderInfoLog(m_uiVertexShader, i32InfoLogLength, &i32CharsWritten, pszInfoLog);
  char* pszMsg = new char[i32InfoLogLength+256];
  sprintf(pszMsg, "Failed to compile vertex shader: %s", pszInfoLog);
  PVRShellSet(prefExitMessage, pszMsg);
  delete [] pszMsg;
  delete [] pszInfoLog;
  return false;
 }

 // Create the shader program
    m_uiProgramObject = glCreateProgram();

 // Attach the fragment and vertex shaders to it
    glAttachShader(m_uiProgramObject, m_uiFragShader);
    glAttachShader(m_uiProgramObject, m_uiVertexShader);

 // Bind the custom vertex attribute "myVertex" to location VERTEX_ARRAY
    glBindAttribLocation(m_uiProgramObject, VERTEX_ARRAY, "myVertex");
 // Bind the custom vertex attribute "myUV" to location TEXCOORD_ARRAY
    glBindAttribLocation(m_uiProgramObject, TEXCOORD_ARRAY, "myUV");

 // Link the program
    glLinkProgram(m_uiProgramObject);

 // Check if linking succeeded in the same way we checked for compilation success
    GLint bLinked;
    glGetProgramiv(m_uiProgramObject, GL_LINK_STATUS, &bLinked);
 if (!bLinked)
 {
  int i32InfoLogLength, i32CharsWritten;
  glGetProgramiv(m_uiProgramObject, GL_INFO_LOG_LENGTH, &i32InfoLogLength);
  char* pszInfoLog = new char[i32InfoLogLength];
  glGetProgramInfoLog(m_uiProgramObject, i32InfoLogLength, &i32CharsWritten, pszInfoLog);
  char* pszMsg = new char[i32InfoLogLength+256];
  sprintf(pszMsg, "Failed to link program: %s", pszInfoLog);
  PVRShellSet(prefExitMessage, pszMsg);
  delete [] pszMsg;
  delete [] pszInfoLog;
  return false;
 }

 // Actually use the created program
 glUseProgram(m_uiProgramObject);

 // Sets the sampler2D variable to the first texture unit
 glUniform1i(glGetUniformLocation(m_uiProgramObject, "sampler2d"), 0);

 // Sets the clear color
 glClearColor(0.6f, 0.8f, 1.0f, 1.0f);

 /*
  Creates the texture.
  Please refer to the training course "Texturing" for a detailed explanation.
 */
 glGenTextures(1, &m_uiTexture);
 glBindTexture(GL_TEXTURE_2D, m_uiTexture);
 GLuint* pTexData = new GLuint[TEX_SIZE*TEX_SIZE];
 for (int i=0; i<TEX_SIZE; i++)
 for (int j=0; j<TEX_SIZE; j++)
 {
  GLuint col = (255L<<24) + ((255L-j*2)<<16) + ((255L-i)<<8) + (255L-i*2);
  if ( ((i*j)/8) % 2 ) col = (GLuint) (255L<<24) + (255L<<16) + (0L<<8) + (255L);
  pTexData[j*TEX_SIZE+i] = col;
 }
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, TEX_SIZE, TEX_SIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, pTexData);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 delete [] pTexData;

 // Create VBO for the triangle from our data

 // Interleaved vertex data
 GLfloat afVertices[] = {-0.4f,-0.4f,0.0f, // Pos
        0.0f,0.0f ,   // UVs
        0.0f,0.0f,1.0f,  // Normals
        0.4f,-0.4f,0.0f,
        1.0f,0.0f ,
        0.0f,0.0f,1.0f,
        0.0f,0.4f ,0.0f,
        0.5f,1.0f,
        0.0f,0.0f,1.0f
};

 glGenBuffers(1, &m_ui32Vbo);

 m_ui32VertexStride = 8 * sizeof(GLfloat); // 3 floats for the pos, 2 for the UVs, 3 for normals

 // Bind the VBO
 glBindBuffer(GL_ARRAY_BUFFER, m_ui32Vbo);

 // Set the buffer's data
 glBufferData(GL_ARRAY_BUFFER, 5 * m_ui32VertexStride, afVertices, GL_STATIC_DRAW);

 // Unbind the VBO
 glBindBuffer(GL_ARRAY_BUFFER, 0);
 return true;
}

/*!****************************************************************************
 @Function  ReleaseView
 @Return  bool  true if no error occured
 @Description Code in ReleaseView() will be called by PVRShell when the
    application quits or before a change in the rendering context.
******************************************************************************/
bool OGLESBasicTnL::ReleaseView()
{
 // Frees the texture
 glDeleteTextures(1, &m_uiTexture);

 // Release Vertex buffer object.
 glDeleteBuffers(1, &m_ui32Vbo);

 // Frees the OpenGL handles for the program and the 2 shaders
 glDeleteProgram(m_uiProgramObject);
 glDeleteShader(m_uiVertexShader);
 glDeleteShader(m_uiFragShader);
 //m_Print3D.DeleteWindow(handle);
 m_Print3D.ReleaseTextures();
 return true;
}

/*!****************************************************************************
 @Function  RenderScene
 @Return  bool  true if no error occured
 @Description Main rendering loop function of the program. The shell will
    call this function every frame.
    eglSwapBuffers() will be performed by PVRShell automatically.
    PVRShell will also manage important OS events.
    Will also manage relevent OS events. The user has access to
    these events through an abstraction layer provided by PVRShell.
******************************************************************************/
bool OGLESBasicTnL::RenderScene()
{
 float aModelViewIT[] =
 {
  cos(m_fAngle), 0, sin(m_fAngle),
  0,    1, 0,
  -sin(m_fAngle), 0, cos(m_fAngle)
 };

 // Clears the color and depth buffer
 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

 /*
  Bind the projection model view matrix (PMVMatrix) to the
  corresponding uniform variable in the shader.
  This matrix is used in the vertex shader to transform the vertices.
 */
 float aPMVMatrix[] =
 {
  cos(m_fAngle), 0, sin(m_fAngle), 0,
  0,    1, 0,    0,
  -sin(m_fAngle), 0, cos(m_fAngle), 0,
  0,    0, 0,    1
 };
 int i32Location = glGetUniformLocation(m_uiProgramObject, "myPMVMatrix");
 glUniformMatrix4fv( i32Location, 1, GL_FALSE, aPMVMatrix);

 /*
  Bind the Model View Inverse Transpose matrix to the shader.
  This matrix is used in the vertex shader to transform the normals.
 */
 i32Location = glGetUniformLocation(m_uiProgramObject, "myModelViewIT");
 glUniformMatrix3fv( i32Location, 1, GL_FALSE, aModelViewIT);

 // Bind the Light Direction vector to the shader
 i32Location = glGetUniformLocation(m_uiProgramObject, "myLightDirection");
 glUniform3f( i32Location, 0, 0, 1);

 // Increments the angle of the view
 m_fAngle += .02f;

 /*
  Draw a triangle.
  Please refer to the training course IntroducingPVRShell for a detailed explanation.
 */

 // Bind the VBO
 glBindBuffer(GL_ARRAY_BUFFER, m_ui32Vbo);

 // Pass the vertex data
 glEnableVertexAttribArray(VERTEX_ARRAY);
 glVertexAttribPointer(VERTEX_ARRAY, 3, GL_FLOAT, GL_FALSE, m_ui32VertexStride, 0);

 // Pass the texture coordinates data
 glEnableVertexAttribArray(TEXCOORD_ARRAY);
 glVertexAttribPointer(TEXCOORD_ARRAY, 2, GL_FLOAT, GL_FALSE, m_ui32VertexStride, (void*) (3 * sizeof(GLfloat)) /* Uvs start after the vertex position */);

 // Pass the normals data
 glEnableVertexAttribArray(NORMAL_ARRAY);
 glVertexAttribPointer(NORMAL_ARRAY, 3, GL_FLOAT, GL_FALSE, m_ui32VertexStride, (void*) (5 * sizeof(GLfloat)) /* Normals start after the position and uvs */);

 // Draws a non-indexed triangle array
 glDrawArrays(GL_TRIANGLES, 0, 3);

 // Unbind the VBO
 glBindBuffer(GL_ARRAY_BUFFER, 0);

 m_Print3D.DisplayDefaultTitle("Window test", "", 0);
 m_Print3D.Flush();

 return true;
}

/*!****************************************************************************
 @Function  NewDemo
 @Return  PVRShell*  The demo supplied by the user
 @Description This function must be implemented by the user of the shell.
    The user should return its PVRShell object defining the
    behaviour of the application.
******************************************************************************/
PVRShell* NewDemo()
{
 return new OGLESBasicTnL();
}

/******************************************************************************
 End of file (OGLESBasicTnL.cpp)
******************************************************************************/

 

 

 

renaissance2010-06-17 22:25:08

[Scott]

Hi,

 

When Print3D draws the text it changes various GL render states and doesn't put them back. If you have a look at the APIRenderStates function that is part of the Print3D code you'll be able to see the states that it changes. This function should give you an idea of what to set after your call to m_Print3D.Flush() to put things back the way they were.

 

I haven't tried to compile your code but my first suggestion would be to move

 

// Actually use the created program
 glUseProgram(m_uiProgramObject);

 

to the beginning of your RenderScene as Print3D uses its own shaders so you need to switch back to yours.

 

Thanks,

 

Scott

[renaissance]

Thank you so much, Scott.

Your method works partially. I do have the rotating triangle back. However, the texture and color is gone. In the attached image, you will see what happend. I am just wondering, when I call  glUseProgram(m_uiProgramObject) again, where did I pass the texture or color information?

 

Thank you,

Renaissance

[Scott]

renaissance wrote:

where did I pass the texture or color information?

 

I'm afraid I can't view your screenshots as you need to upload them somewhere and link to them. Anyway, you bind your texture in your InitView but this is another thing that Print3D changes so you need to add

Code:

glBindTexture(GL_TEXTURE_2D, m_uiTexture);

to your RenderScene so your texture is used.

[renaissance]

Thank you very much, Scott. What you suggested works well in my test.

 

[ernasty]

One really hard to find thing I just figured out is that the Flush() function leaves culling to front faces with clockwise winding.

 

glEnable(GL_CULL_FACE);

glFrontFace(GL_CW);

glCullFace(GL_FRONT);

 

This seems to be the opposite of the winding order I am seeing from my 3ds max exported POD file.  When I add:

 

glFrontFace(GL_CCW);

 

my front faces show up again.