rotating sprites

phil67rpg · 2018-11-12T21:54:39

I am still working on rotating my bullet around my plane sprite I have made some progress. however when move the plane down the bullet is drawn toward the top middle of the screen. when I move the plane to the left the bullet is drawn toward the middle of the left of the screen. although the bullet does move in the same direction as the plane is facing, at least I have solved that problem. I think the problem is in the glRotatef function. here is my code so far. void drawbullet_one() { glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, texture[2]); glPushMatrix(); if (rotate == 0.25f) { angle = 0.0f; } if (rotate == 0.75f) { angle = 180.0f; } if (rotate == 0.5f) { angle = 90.0f; } if (rotate == 0.0f) { angle = 270.0f; } glRotatef(angle, 0.0f, 0.0f, 1.0f); glTranslatef(0.0f, 0.0f + up, 0.0f); glBegin(GL_POLYGON); glTexCoord3f(0.0f, 0.0f, 0.0f); glVertex3f(0.0625f+horizontal, 0.0625f+vertical, 0.0f); glTexCoord3f(1.0f, 0.0f, 0.0f); glVertex3f(-0.0625f+horizontal, 0.0625f+vertical, 0.0f); glTexCoord3f(1.0f, 1.0f, 0.0f); glVertex3f(-0.0625f+horizontal, -0.0625f+vertical, 0.0f); glTexCoord3f(0.0f, 1.0f, 0.0f); glVertex3f(0.0625f+horizontal, -0.0625f+vertical, 0.0f); glEnd(); glPopMatrix(); glDisable(GL_TEXTURE_2D); }

For Beginners 2D C++ OpenGL

Started by phil67rpg November 03, 2018 08:32 PM

9 comments, last by RoamBlade 6 years, 3 months ago

phil67rpg

Author

458

November 12, 2018 02:47 AM

YEAH!!! I solved my problem by putting a glTranslatef in my code .

RoamBlade

124

November 12, 2018 09:54 PM


float r = sqrt(pow(0.5f, 2) + pow(0.5f, 2));

glBegin(GL_POLYGON);
glTexCoord3f(0.0f, 0.0f, 0.0f);

glVertex3f(0.0625f+cos(angle)*r*up+horizontal, 0.0625f+sin(angle)*r*up+vertical, 0.0f);
glTexCoord3f(1.0f, 0.0f, 0.0f);

glVertex3f(-0.0625f+cos(angle)*r*up+horizontal, 0.0625f+sin(angle)*r*up+vertical, 0.0f);
glTexCoord3f(1.0f, 1.0f, 0.0f);

glVertex3f(-0.0625f+cos(angle)*r*up+horizontal, -0.0625f+sin(angle)*r*up+vertical, 0.0f);
glTexCoord3f(0.0f, 1.0f, 0.0f);

glVertex3f(0.0625f+cos(angle)*r*up+horizontal, -0.0625f+sin(angle)*r*up+vertical, 0.0f);
glEnd();

so, my OpenGl is limited, but are you pushing already rotated and translated vertices? as opposed to sending a quad and applying a proper translation*rotation matrix?

rotating sprites

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